Question 1

The primary purpose of inferential statistics is to make a judgment about a population.

Accepted Answer

Inferential statistics uses sample data to make inferences or judgments about a population, such as estimating a population mean or testing a hypothesis about a population proportion.

Question 2

The standard deviation eliminates the drawback of having the measure of dispersion in squared units rather than the original measurement units.

Accepted Answer

The standard deviation is a measure of dispersion that is expressed in the original measurement units, unlike variance, which is expressed in squared units. Therefore, it eliminates the drawback of having the measure of dispersion in squared units.

Question 3

The average deviation score is frequently used in business research studies.

Accepted Answer

False

Question 4

The normal distribution is represented by the normal curve.

Accepted Answer

The normal distribution is represented by the normal curve, which is a bell-shaped curve that is symmetrical around the mean.

Question 5

If between 125 and 150 units of a product have been produced each day during the past month, the range of this production is 150 units.

Accepted Answer

The range is calculated as the difference between the maximum and minimum values, so the range is 150 - 125 = 25 units.

Question 6

The mode is the measure of central tendency that identifies the value that occurs most often.

Accepted Answer

The statement is true.

Question 7

The standardized normal distribution is a purely theoretical probability distribution and is of little use in inferential statistics.

Accepted Answer

The standardized normal distribution is actually very useful in inferential statistics. It allows us to calculate probabilities associated with any normal distribution, regardless of its mean or standard deviation. This is important in hypothesis testing and confidence interval estimation, among other things.

Question 8

Percentage frequency is the long-run relative frequency with which an event will occur.

Accepted Answer

This is probability.

Question 9

"As sample size increases, the distribution of sample means of samples of size n (when randomly selected) approaches a normal distribution" is a fundamental assumption of the central-limit theorem.

Accepted Answer

This is a true statement and a key concept in the central limit theorem. As sample size increases, the distribution of sample means becomes more and more normal, regardless of the distribution of the population.

Question 10

A confidence range is a specified range of numbers within which a population mean is expected to lie.

Accepted Answer

The answer of A confidence range is a specified range...

Question 11

A frequency distribution of a sample is called a probability distribution.

Accepted Answer

A frequency distribution is simply a way to organize data into intervals or categories and count the number of occurrences. A probability distribution, on the other hand, not only shows the frequency but also assigns a probability to each outcome or category. The sum of all probabilities in a probability distribution must be equal to 1.

Question 12

The mean is simply the arithmetic average.

Accepted Answer

The mean is indeed the arithmetic average, which is found by adding up all the values in a dataset and then dividing by the number of values.

Question 13

The standardized normal distribution has a mean of 1.0 and a standard deviation of zero.

Accepted Answer

The standardized normal distribution has a mean of 0 and a standard deviation of 1.

Question 14

A common practice in research is to use the 75 percent confidence interval about the mean in research studies.

Accepted Answer

The 75 percent confidence interval is a common practice in research studies because it provides a reasonable balance between the width of the interval and the level of confidence.

Question 15

Population parameters are measured characteristics of a specific population.

Accepted Answer

Population parameters are numerical values that describe a characteristic of a population, such as the population mean, population standard deviation, or population proportion. They are the true values of these characteristics for the entire population and are typically unknown and estimated using sample statistics.

Question 16

A frequency distribution is a set of data organized by summarizing the number of times a particular value of a variable occurs.

Accepted Answer

This statement is true.

Question 17

The standardized value of Z is computed by the formula: Z = (X - m)/s.

Accepted Answer

This is true. The standardized value of Z is calculated by subtracting the mean (m) from the observed value (X) and then dividing the result by the standard deviation (s). This formula allows us to compare values from different normal distributions on the same scale.

Question 18

A point estimate is an estimate of the population mean in the form of a single value.

Accepted Answer

A point estimate is indeed an estimate of the population mean in the form of a single value.

Question 19

One hundred percent of the scores in a normal distribution fall within plus or minus two standard deviations of the mean.

Accepted Answer

Almost all (99.7 percent)of its values are within +/- 3 standard deviations from its mean.

Question 20

The midpoint of a distribution, above which and below which half of the scores fall, is called the mode.

Accepted Answer

The midpoint of a distribution, above which and below which half of the scores fall, is actually the median. The mode is the most commonly occurring score in a distribution.

Quiz 17: Determination of Sample Size: a Review of Statistical Theory