chapter 1

Of the following dotplots, which represents the set of data that has the greatest standard deviation?

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A random sample of 374 United States pennies was collected, and the age of each penny was determined. According to the boxplot below, what is the approximate interquartile range (IQR) of the ages?

• 8

• 10

• 16

• 40

• 50

The histogram above shows the number of minutes needed by 45 students to finish playing a computer game. Which of the following statements is correct?

• (A) The distribution is skewed to the right.

• (B) The distribution is skewed to the left.

• (C) The distribution appears to be normal.

• (D) The distribution appears to be chi-square.

• (E) The distribution appears to be uniform.

The histogram below displays the frequencies of waiting times, in minutes, for 175 patients in a dentist’s office. Which of the following could be the median of the waiting times, in minutes?

• 2.5

• 7.25

• 12.25

• 15

• 17.5

Data were collected on the amount, in dollars, that individual customers spent on dinner in an Italian restaurant.
The quartiles for these data are given below.
Which of the following statements must be true for these customers?

• (A) At least half of the customers spent less than or equal to $44.27 and at least half spent greater than or equal
  to $44.27.

• (B) Seventy-five percent of the customers spent between $36.27 and $58.97.

• (C) Twenty-five percent of the customers spent less than or equal to $58.97 and the remaining 75 percent spent
  greater than or equal to $58.97.

• (D) The mean amount spent by customers is $44.27.

• (E) A majority of customers spent $44.27.

The scatterplot below displays the price in dollars and quality rating for 14 different sewing machines.
(a) Describe the nature of the association between price and quality rating for the sewing machines.
The data show a association between price and quality rating for these sewing machines. (hint: two words: describe the strength and direction)

The scatterplot below displays the price in dollars and quality rating for 14 different sewing machines.
(a) Describe the nature of the association between price and quality rating for the sewing machines.
Continued: The form of the association (does or does not) appear to be linear.

Answer explanation

strongness and direction