Chapter 3 Quiz Review

What statistic is denoted by the Greek letter "µ" (mu)?

• Mode

• Median

• Mean

• Standard Deviation

Answer explanation

The mean for a population is denoted by the Greek letter "µ," and the mean for a sample is denoted by "M."

What is the goal of central tendency?

• To find the single score that is most typical/representative of the entire group.

• To add all the scores in the distribution and dividing by the number of scores.

• To divide a distribution in half so that 50% of the individuals lie above or below the mean.

• To standardize scores in hopes of making values more comparable.

Answer explanation

Central tendency is a statistical measure to determine a single score that defines the center of a distribution. The main goal is to find the single score that is most typical/representative of the entire group.

• True

• False

One sample has n = 6 scores with a mean of M = 4. A second sample has n = 4 scores with a mean of M = 9. If the two samples are combined, what is the mean for the combined sample?

• M = 4

• M = 5

• M = 6

• M = 7

Answer explanation

The combined sample has n = 10 scores. The total for the first sample is ΣX = 24 (6 scores X Mean of 4). The total for the second sample is ΣX = 36 (4 scores X Mean of 9). The combined total is ΣX = 60, making the mean M = 6.

A sample of n = 7 scores has a mean of M = 5. What is the value of ΣX for this sample?

• ΣX = 24

• ΣX = 32

• ΣX = 28

• ΣX = 35

Answer explanation

The total for this problem can be solved by multiplying the mean (M = 5) by the number of scores (n = 7) to get ΣX = 35.

Adding a new score to a distribution will always change the mean.

• True

• False

Answer explanation

If the score is equal to the mean, it will not change the mean.

Changing the value of a score in a distribution will always change the mean.

• True

• False

Answer explanation

Adding a score (or removing a score) has the same effect on the mean whether the original set of scores is a sample or a population.

In a recent survey comparing picture quality for three brands of color televisions, 63 people preferred brand A, 29 people preferred brand B and 58 people preferred brand C. What is the mode for this distribution?

• Brand A

• 63 people

• 58 people

• Brand C

Answer explanation

The mode is the score OR category (in this case, brands of television) that have the greatest frequency. Brand A had the most frequent votes, making it our mode for the given distribution.

If a distribution has a mean of 75 and a median of 70, what can we already conclude?

• The distribution is negatively skewed.

• The distribution is bimodal.

• The distribution is positively skewed.

• The mean is less than the mode.

Answer explanation

If the mean is greater than the median within a distribution, we can conclude that our distribution is positively skewed since our mean is being pulled farther up.

Which measure of central tendency is used to assess data from a nominal scale?

• Mean

• Median

• Mode

• Variability

Answer explanation

Recall that the categories that make up a nominal scale are differentiated only by name. Because nominal scales do not measure quantity (distance or direction), it is impossible to compute a mean or a median for data, making the mode the only viable option for describing central tendency.