Question 1

When it is impossible to obtain all the scores in a population,the best estimate of the population mean is the

Accepted Answer

When it is impossible to obtain all the scores in a population, the best estimate of the population mean is the sample mean. This is because the sample mean provides an unbiased estimate of the population mean and is an effective way to estimate the population's central tendency based on the available data. However, it is important to ensure that the sample is representative of the population to obtain an accurate estimate of the population mean.

Question 2

Five students took a personality test.Their deviation scores were -4,+3,+1,-2,+2.Assuming that these scores form a normal distribution,which deviation(s)represent the score(s)having the highest frequency?

Accepted Answer

In a normal distribution, the mean (average) score is the most frequent. The scores are -4, +3, +1, -2, +2. The mean is calculated as (-4 + 3 + 1 - 2 + 2) / 5 = 0. The score closest to the mean is +1, which is the most frequent.

Question 3

Five students took a personality test.Their deviation scores were -4,+3,+1,-2,+2.Assuming that these scores form a normal distribution,which deviation represents the highest raw score?

Accepted Answer

The deviation score of +3 represents the highest raw score because in a normal distribution, the highest raw score is associated with the highest deviation score.

Question 4

The population mean is estimated by

Accepted Answer

The best way to estimate the population mean is by calculating the mean of a random sample drawn from the population. This is because a random sample is representative of the population and allows for inference to the population. Simply calculating the mean of as many scores as we can get from the population (option A) is not practical or feasible in many cases. Transforming the mean of a sample to reflect the size of the population (option C) is not necessary as the sample mean is already an estimate of the population mean. Calculating all measures of central tendency for a random sample drawn from the population (option D) is not necessary as the mean is a sufficient statistic for estimating the population mean.

Question 5

When deciding which type of measure of central tendency is appropriate,we consider the scale of measurement used to measure the

Accepted Answer

The measure of central tendency (mean, median, mode) that is appropriate depends on the scale of measurement used to measure the variable being studied. If the variable is measured on an interval or ratio scale, the mean is the appropriate measure of central tendency. Therefore, the appropriate choice in this scenario is the dependent variable (D) since it is the variable being measured and may be measured on an interval or ratio scale.

Question 6

The equipment failed to record the reaction time for one trial in an experiment.The reaction times (in milliseconds)for the other trials were 505,630,490,650,and 560.What is the best guess for the missing value?

Accepted Answer

The best guess for the missing value is the mean (average) of the given reaction times. Adding the given reaction times (505, 630, 490, 650, and 560) gives a total of 2835. Dividing this total by the number of given values (5) gives an average of 567 milliseconds.

Question 7

For the following set of scores,what is (are)  ?
 7,8,10,10,11,12,13,13,15

Accepted Answer

To find the answer, we need to calculate the deviation of each score from the mean. 
Mean = (7+8+10+10+11+12+13+13+15)/9 = 11
Deviations:
7-11 = -4
8-11 = -3
10-11 = -1
10-11 = -1
11-11 = 0
12-11 = 1
13-11 = 2
13-11 = 2
15-11 = 4

Therefore, the deviation scores are: -4, -3, -1, -1, 0, 1, 2, 2, 4. The only option that matches this is B.

Question 8

When we graph results from an experiment where the independent variable is on a nominal scale,which type of graph is appropriate

Accepted Answer

When the independent variable is on a nominal scale, the appropriate type of graph is a bar graph. This type of graph allows the researcher to display frequencies or percentages of different categories in a clear, easy-to-understand way. A bar graph consists of vertical or horizontal bars that represent the different categories of the independent variable, with the height or length of each bar corresponding to the frequency or percentage of each category. Therefore, a bar graph would be the best choice to graph the results from an experiment where the independent variable is on a nominal scale.

Question 9

µ is the symbol for the

Accepted Answer

µ is the symbol for the population mean. The median is commonly represented by M or ȷ, the mode is not represented by a specific symbol, and sample mean is represented by x̄.

Question 10

When the mean is used to predict scores,a deviation  indicates

Accepted Answer

A deviation indicates the difference between the predicted score and the score an individual actually gets. The mean is often used to predict scores, and a deviation from the mean indicates how far away a particular score is from the predicted value.

Question 11

When we graph the results of an experiment,the Y axis indicates the

Accepted Answer

The Y-axis of a graph typically represents the dependent variable, which is the variable being measured or observed. The measure of central tendency used for the dependent variable, such as the mean or median, is often used to summarize the data and create a line or bar graph.

Question 12

In a graph of the relationship between the level of noise in an environment and the number of errors a person makes,the _____ is on the X axis and the _____ is on the Y axis.

Accepted Answer

In a graph of the relationship between the level of noise in an environment and the number of errors a person makes, the level of noise is the independent variable and is plotted on the x-axis, while the number of errors is the dependent variable and is plotted on the y-axis. Therefore, choice B is the correct answer.

Question 13

On any graph,a horizontal line of data points indicates that

Accepted Answer

A horizontal line indicates that there is no change in the Y scores as the X scores change, indicating that there is no relationship present.

Question 14

The best predictor of an individual score in a sample of scores is the

Accepted Answer

The mean of a sample of scores is the best predictor of an individual score within that sample because it represents the central tendency or average of all the scores, providing a single value that summarizes the entire set of data.

Question 15

When deciding which type of graph (bar,line,histogram,etc. )is appropriate,we consider the characteristics of the

Accepted Answer

The choice of graph type often depends on the nature of the independent variable, as it determines how data points are plotted and visualized.

Question 16

Based on the following results of an experiment,how many errors would a person who drank 4 oz.of alcohol make?

Accepted Answer

The answer of Based on the following results of an...

Question 17

Which of the following graphs does not indicate the presence of a relationship?

Accepted Answer

The answer of Which of the following graphs does not...

Question 18

When using the mean to predict scores,error is represented by

Accepted Answer

When using the mean to predict scores, error is represented by the deviation of a score from the mean. This measures how far off each individual score is from the average predicted value based on the mean.

Question 19

Five students took a personality test.Their deviation scores were -4,+3,+1,-2,+2.Assuming that these scores form a normal distribution,which of the following orders represents their ranking in terms of frequency,from highest to lowest?

Accepted Answer

In a normal distribution, scores closest to the mean (in this case, 0) are the most frequent. Thus, +1 and -2 (closest to 0) are more frequent than +2 and -4, and +3 is the least frequent. This matches option A, where +1 and -2 are most frequent, followed by +2 and -4, with +3 being least frequent.

Question 20

When we graph results from an experiment,a line graph is appropriate when

Accepted Answer

A line graph is appropriate when the independent variable is interval or ratio, as it allows for the depiction of trends or changes over a continuous range.

Quiz 4: Measures of Central Tendency;the Mean, median, and Mode