Question 1

Which is true about a sample that is heterogeneous?
A) It has a wide variation in scores.
B) Scores will be clustered around the mean.
C) The measure of range will be small.
D) The standard deviation cannot be calculated.

Accepted Answer

Heterogeneous samples have a wide variation in scores.Such samples will have a wide standard deviation,with scores that can be far from the mean score.

Question 2

A researcher studies the effects of a nursing intervention on a desired patient outcome and discovers a statistically significant difference between groups receiving the intervention and those not receiving the intervention.The researcher concludes that the intervention is effective.This researcher has made a
A) generalization.
B) statistical inference.
C) type I error.
D) type II error.

Accepted Answer

A statistical inference is made from the study findings obtained from a specific sample and applied to the target population.Generalizations are made when information gained from a specific instance is generalized to the general population.A type I error occurs when a researcher incorrectly states that something is significant when it is not.A type II error occurs when a researcher declares the null hypothesis to be true when it is not.

Question 3

In a data set that has a normal distribution what percent of scores will be within two standard deviations above or below the mean?
A) 34
B) 68
C) 95
D) 99

Accepted Answer

In the normal curve,95% of the scores will be within two standard deviations above or below the mean.The other three statements are incorrect.

Question 4

Which describes the mode of a data set?
A) The appropriate measure of central tendency for interval data
B) The appropriate measure of central tendency for ordinal data
C) The exact center of scores for nominal data
D) The score value occurring with greatest frequency

Accepted Answer

The mode represents the score that occurs with greatest frequency in a data set.The mode is the appropriate measure of central tendency for nominal data,not for interval or ordinal data.

Question 5

A researcher collects scores measuring weight among school-age children who are in an obesity prevention program and notes that several students are morbidly obese with most students falling within or below the 85th percentile for weight.The scores from the morbidly obese children will affect which measure of central tendency the most?
A) Mean
B) Median
C) Mode
D) All the above are affected equally.

Accepted Answer

The mode and median are not as affected by outliers as is the mean.The other three statements are incorrect.

Question 6

A researcher will present demographic data about ethnicity,gender,and diagnoses about a study population using which method?
A) Continuous frequency distribution
B) Grouped frequency distribution
C) Percentage frequency distribution
D) Ungrouped frequency distribution

Accepted Answer

Ungrouped frequency distribution tables are used to present categorical data,such as demographic data,when categories are discrete.Continuous data are presented using grouped data tables.Ungrouped frequency distribution tables are used to present categorical data,such as demographic data,when categories are discrete.A percentage distribution indicates the percentage of subjects who fall into a category and is often used when comparing scores from findings with other data samples.

Question 7

The concept of degrees of freedom refers to
A) the level of significance for a study.
B) the standard deviation from the mean among data.
C) the variability of a given score based on other scores.
D) whether statistical analysis is one- or two-tailed.

Accepted Answer

Degrees of freedom involve the freedom of a score value to vary given the other existing scores.Degrees of freedom do not directly affect the level of significance,standard deviation,or tailedness.

Question 8

A researcher plans to apply a one-tailed test of significance when analyzing data from a study.Which is true about using this test?
A) The researcher will be unable to predict whether differences are greater than or less than the mean value.
B) This is a nondirectional hypothesis,so values will not tend to vary in a specific direction.
C) This may increase the possibility of a type I error when evaluating the significance of the findings.
D) This will decrease the possibility of a type II error when drawing conclusions about the data.

Accepted Answer

A one-tailed hypothesis means that the data tend to vary in a certain direction.One-tailed statistical tests are uniformly more powerful than two-tailed tests and decrease the possibility of a type II error.A one-tailed hypothesis increases a study's power and improves the ability to predict outcomes.A one-tailed test is a unidirectional hypothesis,with values tending to vary in a specific direction.A one-tailed test does not increase the chance of a type I error.

Question 9

When a researcher concludes that study findings are applicable to the total population,this is an example of
A) generalization.
B) inference.
C) probability.
D) significance.

Accepted Answer

Generalizations are made when information gained from a specific instance is generalized to the general population.A statistical inference is made from the study findings obtained from a specific sample and applied to the target population.Probability refers to the likelihood that a variable fall at a certain point in the range of data scores.Significance is a value indicating the chance that values are from different groups when the value of one group is not within the range of values of another group.

Question 10

Assuming a normal distribution,what range of numbers would include two thirds of the scores if they ranged from 50 to 99,M = 75,and SD = 5? Between
A) 55 and 95
B) 65 and 85
C) 68 and 82
D) 70 and 80

Accepted Answer

In the normal curve,68% of scores will be within 1 standard deviation above or below the mean.In the example,two thirds of scores (66%)fall between 70 and 80.The mean = 75 and the SD = 5 for this sample.It follows that scores will fall between 1 standard deviation below (75 - 5 = 70)and 1 standard deviation above the mean (75 + 5 = 80).The other three statements are incorrect.

Question 11

The median scores of two groups participating in a study are exactly the same for a particular variable.This suggests that the
A) average score is the same for both groups.
B) the middle score is the same for both groups.
C) the most frequent score is the same for both groups.
D) groups are very much alike in relation to the variable.

Accepted Answer

The median is a measure of central tendency and indicates the middle score of a group,but does not indicate the variability of the scores around the mean.A measure of dispersion is required to demonstrate the distribution of scores.The same median score does not mean the average score,or the mean,is the same.The same median score does not mean that the most frequent,or mode,is the same.The same median does not equate to sameness in other ways.

Question 12

A researcher conducts a study and calculates a mean value of 100 in a set of scores ranging from 90 to 300.Which other measure will the researcher report when describing central tendency in this data set?
A) Median
B) Mode
C) Range
D) Variance

Accepted Answer

The median value is not affected by extreme scores and should also be reported.The mean is most affected by outliers in a study.In this case,the mean value is very close to values at one end of the scale and not toward the center,indicating that a normal curve is not present.The mode will describe the most frequent score.The range and variability will be reported,but do not describe central tendency.

Question 13

A researcher conducts a power analysis for a study in which there was no difference between control and experimental group scores and identifies a power level of 0.75 and a level of significance of 0.05.What will this researcher do?
A) Alter measurement methods to detect larger changes in scores.
B) Conclude that the null hypothesis is true.
C) Consider repeating the study using a larger sample.
D) Lower the level of significance to 0.01.

Accepted Answer

The minimum acceptable power level is 0.80.To improve this,a larger sample size may be necessary.Because the level of power is too low,the researcher cannot draw valid conclusions about the data.Measurement methods that measure large changes decrease the effect size,which decreases the power.The level of significance does not indicate whether the null hypothesis is true or false,merely the probability of making an error in judging whether it is true or false.Lowering the level of significance lowers the power.

Question 14

A researcher wishes to present data identifying pain scores for a group of subjects using a grouped frequency distribution table.Which is true about using this method?
A) Each group must have equivalent ranges in scores.
B) Ranges may overlap from one group to the next.
C) Some data may not fit into any group.
D) There should be no more than five groups of scores.

Accepted Answer

In grouped frequency distribution tables,each group of scores must have equivalent ranges.Ranges should be discrete without overlapping so that each datum will fit into only one group.The ranges must be exhaustive so that all data will fit into a group.There should be at least 5 and no more than 20 groups.

Question 15

In research,the probability that any data score will be within a certain range of a mean value is calculated based on the theory of
A) frequency.
B) inference.
C) levels of significance.
D) the normal curve.

Accepted Answer

A normal curve is a theoretical frequency distribution of all possible values in a population,with a 95% probability that any value from that population will fall within 2 standard deviations of the mean.Frequency refers to the number of times a specific value occurs.A statistical inference is made from the study findings obtained from a specific sample and applied to the target population.Levels of significance is a value indicating the chance that values are from different groups when the value of one group is not within the range of values of another group.

Question 16

When a data set has a normal distribution curve,which statement is true about the data?
A) The mean is the lowest value.
B) The median is the highest value.
C) The mode is the central value.
D) The mode,median,and mean are equal values.

Accepted Answer

In a normal distribution curve,the mode,median,and mean are equal.The other three statements are incorrect.

Question 17

A researcher develops a study to examine the effects of Keep Yourself Safe Screening (KYSS)on the incidence of intimate partner violence (IPV).The study level of significance is 0.05.The null hypothesis,that KYSS will have no effect on IPV,is found to be true.When reviewing the study for type II errors,the reviewer understands that
A) a level of significance of 0.01 would decrease the risk of a type II error.
B) the level of significance does not affect the chance of a type II error.
C) there is a 5% chance that the null hypothesis is false.
D) there is a 5% chance that the null hypothesis is true.

Accepted Answer

A type II error occurs when the null hypothesis is regarded as true but is actually false.A level of significance of 0.05 indicates a 5% chance of a type II error.The risk of a type II error increases when the level of significance is less.A level of significance of 0.05 indicates a 5% chance of a type II error that occurs when the null hypothesis regarded as true but is actually false but does not affect the likelihood that the null hypothesis is true or false.

Question 18

In a study to examine motivational techniques to help adolescent smokers to quit smoking,the null hypothesis states that the intervention will have no effect on this population.The researcher establishes a level of significance of 0.01.When analyzing the data,the researcher concludes that there is a significant difference between subjects receiving the intervention and those who do not.In this study,a type I error means there is a
A) 1% chance that the conclusion is wrong.
B) 1% chance that the conclusion is correct.
C) 99% chance that the conclusion is wrong.
D) 99% chance that the null hypothesis is correct.

Accepted Answer

Type I error occurs when the null hypothesis is rejected when it is actually correct.A significance of 0.01 indicates a 1% chance that the null hypothesis is correct when it is rejected.There is a 99% chance,in this study,that the conclusion is correct and the null hypothesis is incorrect.

Question 19

A researcher studying subjects who have pulmonary disease presents a data set to describe the different conditions the subjects experience and reports the following data.Which number represents the mode for this data set? Asthma 4
COPD 6
Chronic bronchitis 4
Pulmonary hypertension 7
A) 4.0
B) 5.25
C) 6.5
D) 7.0

Accepted Answer

The mode is the number that occurs most frequently in a data set.In this case,there are two groups of 4,so 4 is the mode.The other three statements are incorrect.

Question 20

When comparing a study with a level of significance of 0.05 with a study having a level of significance of 0.01,the researcher knows that the study with the level of significance of 0.05 is more likely to have a
A) correct null hypothesis.
B) generalizable finding.
C) type I error.
D) type II error.

Accepted Answer

There is a greater risk of a type I error with a 0.05 level of significance than with a 0.01 level of significance.A type I error carries a greater risk of rejecting a null hypothesis when it is true,but does not increase the likelihood of a correct null hypothesis.The type I error does not affect the generalizability of the findings.There is a greater risk of a type II error with a 0.01 level of significance than with a 0.05 level of significance.

Quiz 11: Understanding Statistics in Research

Which is true about a sample that is heterogeneous?

In a data set that has a normal distribution what percent of scores will be within two standard deviations above or below the mean?

Which describes the mode of a data set?

A researcher will present demographic data about ethnicity,gender,and diagnoses about a study population using which method?

The concept of degrees of freedom refers to

A researcher plans to apply a one-tailed test of significance when analyzing data from a study.Which is true about using this test?

When a researcher concludes that study findings are applicable to the total population,this is an example of

Assuming a normal distribution,what range of numbers would include two thirds of the scores if they ranged from 50 to 99,M = 75,and SD = 5? Between

The median scores of two groups participating in a study are exactly the same for a particular variable.This suggests that the

A researcher conducts a study and calculates a mean value of 100 in a set of scores ranging from 90 to 300.Which other measure will the researcher report when describing central tendency in this data set?

A researcher conducts a power analysis for a study in which there was no difference between control and experimental group scores and identifies a power level of 0.75 and a level of significance of 0.05.What will this researcher do?

A researcher wishes to present data identifying pain scores for a group of subjects using a grouped frequency distribution table.Which is true about using this method?

In research,the probability that any data score will be within a certain range of a mean value is calculated based on the theory of

When a data set has a normal distribution curve,which statement is true about the data?

A researcher studying subjects who have pulmonary disease presents a data set to describe the different conditions the subjects experience and reports the following data.Which number represents the mode for this data set? Asthma 4 COPD 6 Chronic bronchitis 4 Pulmonary hypertension 7

When comparing a study with a level of significance of 0.05 with a study having a level of significance of 0.01,the researcher knows that the study with the level of significance of 0.05 is more likely to have a