Q: Which formula would you use to find the class width for a frequency distribution if the minimum value is 15, the maximum is 88, and you want 6 classes?

$$(\text{max} - \text{min}) / \text{number of classes}$$

Q: A data set has the following values: 10, 30, 4, 36, x. If the mean is 20, what is the value of x?

$$x = 20 \times 5 - (10 + 30 + 4 + 36) = 20$$

Question 1

Which of the following best describes the variable 'Yelp rating' as shown in the bar graph for Hot Doug’s Restaurant?

Accepted Answer

Quantitative and discrete, because ratings are counted in whole numbers.

Question 2

In the Hot Doug’s Yelp ratings graph, what should be labeled on the x-axis and y-axis, respectively?

Accepted Answer

x-axis: Yelp Star Rating; y-axis: Number of Ratings

Question 3

Which type of bias is most likely present if a survey about college savings is conducted only among parents attending a private school open house?

Accepted Answer

Sampling bias

Question 4

A researcher wants to estimate the average amount saved for college by randomly selecting 10 families from each grade level at a high school. Which sampling method is this?

Accepted Answer

Stratified sampling

Question 5

Which level of measurement is represented by the 'Yelp Star Rating' variable (1-5 stars)?

Accepted Answer

Ordinal

Question 6

Suppose the mean amount saved for college in a sample is $$\8$$,000$$, but one family has saved $$\$$100,000. $$Which measure of central tendency would best represent a 'typical' family’s savings?

Accepted Answer

Median, because it is resistant to outliers.

Question 7

If a frequency distribution for Yelp ratings is heavily concentrated at 5 stars with a long tail toward lower ratings, the distribution is:

Accepted Answer

Skewed left

Question 8

Which of the following is a potential problem with the 'Most Popular Ways to Save for College' graphic (second image)?

Accepted Answer

The heights of the dollar signs exaggerate differences because the images are not proportional to the percentages.

Question 9

Which of the following would improve the accuracy of the 'Most Popular Ways to Save for College' graphic?

Accepted Answer

Use proportional bar heights to represent the percentages.

Question 10

A survey reports that 31% of families use mutual funds to save for college. If this value is based on a sample of 500 families, what is this value called?

Accepted Answer

A statistic, because it describes the sample.

Question 11

If the mean and median of a data set are equal, which of the following is most likely true about the shape of the distribution?

Accepted Answer

It is symmetric.

Question 12

Which formula would you use to find the class width for a frequency distribution if the minimum value is 15, the maximum is 88, and you want 6 classes?

Accepted Answer

$$(	ext{max} - 	ext{min}) / 	ext{number of classes}$$

Question 13

A researcher wants to study the effect of a new teaching method on test scores. She randomly assigns students to two groups and applies the new method to one group. This is an example of:

Accepted Answer

A designed experiment

Question 14

Which of the following best describes a confounding variable in a study about college savings?

Accepted Answer

A variable that affects the outcome but is not the explanatory variable.

Question 15

A sample of 40 households reports the number of cars owned as follows: 0 (3 households), 1 (18 households), 2 (14 households), 3 (5 households). What is the relative frequency for households owning 2 cars?

Accepted Answer

$$\frac{14}{40} = 0.35$$

Question 16

Which of the following is NOT a resistant statistic?

Accepted Answer

Mean

Question 17

If a survey is conducted by asking people at a shopping mall, which sampling method is being used?

Accepted Answer

Convenience sampling

Question 18

Which of the following best describes the difference between stratified and cluster sampling?

Accepted Answer

Stratified: sample some individuals from every group; Cluster: sample every individual from some groups.

Question 19

A data set has the following values: 10, 30, 4, 36, x. If the mean is 20, what is the value of x?

Accepted Answer

$$x = 20 	imes 5 - (10 + 30 + 4 + 36) = 20$$

Introductory Statistics Test 1 Review – Step-by-Step Study Guidance

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