Q: Which formula should you use to find the class width for a frequency distribution?

$$ \text{Class width} = \frac{\text{max} - \text{min}}{\text{number of classes}} $$, \, \text{then round UP to a convenient whole number}

Question 1

Which of the following best describes the variable 'Yelp rating (1-5 stars)' as shown in the Hot Doug’s Restaurant graph?

Accepted Answer

Quantitative and discrete, because it takes on countable values

Question 2

A researcher wants to estimate the average time students spend studying per week. She divides students by major and randomly selects 10 students from each major. Which sampling method is this?

Accepted Answer

Stratified sampling

Question 3

Which level of measurement is represented by the variable 'class rank' (1st, 2nd, 3rd, ...)?

Accepted Answer

Ordinal

Question 4

A survey reports that 31% of families use mutual funds to save for college. This value is a:

Accepted Answer

Statistic, because it is based on a sample

Question 5

Which of the following is an example of a continuous variable?

Accepted Answer

Time spent studying (in hours)

Question 6

A frequency distribution table lists the number of students in each grade (A, B, C, D, F). What type of variable is 'grade'?

Accepted Answer

Qualitative

Question 7

A researcher selects every 10th person from a list of conference attendees. What sampling method is this?

Accepted Answer

Systematic sampling

Question 8

Which of the following best describes the distribution of Yelp ratings for Hot Doug’s Restaurant, as shown in the bar graph?

Accepted Answer

Skewed left

Question 9

If a data set is highly skewed right due to a few very large values, which measure of central tendency is most appropriate to describe the center?

Accepted Answer

Median

Question 10

Which formula should you use to find the class width for a frequency distribution?

Accepted Answer

$$ 	ext{Class width} = \frac{	ext{max} - 	ext{min}}{	ext{number of classes}} $$, \, 	ext{then round UP to a convenient whole number}

Question 11

A bar graph uses 3D dollar signs of different sizes to represent percentages. What is a potential problem with this type of graph?

Accepted Answer

The 3D shapes may exaggerate differences and mislead viewers

Question 12

Which of the following is true about the mean and median in a perfectly symmetric, unimodal distribution?

Accepted Answer

Mean = Median = Mode

Question 13

A researcher observes the effect of a new teaching method on test scores by randomly assigning students to two groups and comparing their results. What type of study is this?

Accepted Answer

Designed experiment

Question 14

Which of the following is an example of response bias?

Accepted Answer

Asking a question in a way that suggests a preferred answer

Question 15

Given the data set: 10, 30, 4, 36, x. If the mean is 20, what is the value of x?

Accepted Answer

$$ x = 0 $$

Question 16

A sample of 8 employees has ages: 22, 24, 24, 27, 30, 31, 45, 58. What is the mean age? (Round to two decimal places)

Accepted Answer

$$ 32.63 $$

Question 17

Which of the following best describes a resistant statistic?

Accepted Answer

A statistic that is not substantially changed by extreme values

Question 18

A survey of 40 households records the number of cars owned: 0 (3 households), 1 (18), 2 (14), 3 (5). What is the relative frequency for households owning 2 cars? (Round to two decimal places)

Accepted Answer

$$ 0.28 $$

Question 19

Which of the following is an example of under-representation in a sample?

Accepted Answer

A sample includes fewer seniors than their proportion in the population

Question 20

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

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

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