Chapter 1 Data Analysis

You record the age, marital status, and earned income of a sample of 1463 women. The number and type of variables you have recorded are

• 3 quantitative, 0 categorical.

• 4 quantitative, 0 categorical.

• 3 quantitative, 1 categorical.

• 2 quantitative, 1 categorical.

• 1 quantitative, 2 categorical.

The students in Mr. Tyson’s high school statistics class were recently asked if they would prefer a pasta party, a pizza party, or a donut party. The following bar graph displays the data.

The graph is misleading because:

• it should be a histogram, not a bar graph.

• there should not be gaps between the bars.

• the bars should be arranged in decreasing order by height.

• the vertical axis scale should start at 0.

• preferred party should be on the vertical axis and num-ber of students should be on the horizontal axis.

Forty students took a statistics test worth 50 points. The dotplot displays the data. The third quartile is:

• 45

• 44

• 43

• 32

• 23

Realtors collect data in order to serve their clients more effectively. In a recent week, data on the age of all homes sold in a particular area were collected and displayed in this histogram.

Which of the following could be the median age?

• 19 years

• 24 years

• 29 years

• 34 years

• 39 years

Realtors collect data in order to serve their clients more effectively. In a recent week, data on the age of all homes sold in a particular area were collected and displayed in this histogram.

Which of the following is most likely true?

• mean > median, range < IQR

• mean < median, range < IQR

• mean > median, range > IQR

• mean < median, range > IQR

• mean = median, range > IQR

The standard deviation of the distribution of house age is about 16 years. Interpret this value.

• The age of all houses in the sample is within 16 years of the mean.

• The gap between the youngest and oldest house is 16 years.

• The age of all the houses in the sample is 16 years from the mean.

• The gap between the first quartile and the third quar-tile is 16 years.

• The age of the houses in the sample typically varies by about 16 years from the mean age.

The mean salary of all female workers is $35,000. The mean salary of all male workers is $41,000. What must be true about the mean salary of all workers?

• It must be $38,000.

• It must be larger than the median salary.

• It could be any number between $35,000 and $41,000.

• It must be larger than $38,000.

• It cannot be larger than $40,000.

A survey was designed to study how business operations vary by size. Companies were classified as small, medium, or large. Questionnaires were sent to 200 randomly selected businesses of each size. Because not all questionnaires are returned, researchers decided to investigate the relationship between the response rate and the size of the business. The data are given in the following two-way table.

What percent of all small companies receiving ques-tionnaires responded?

• 12.5%

• 20.8%

• 33.3%

• 50.8%

• 62.5%

A survey was designed to study how business operations vary by size. Companies were classified as small, medium, or large. Questionnaires were sent to 200 randomly selected businesses of each size. Because not all questionnaires are returned, researchers decided to investigate the relationship between the response rate and the size of the business. The data are given in the following two-way table.

Which of the following conclusions seems to be supported by the data?

• There are more small companies than large companies in the survey.

• Small companies appear to have a higher response rate than medium or big companies.

• Exactly the same number of companies responded as didn’t respond.

• Overall, more than half of companies responded to the survey.

• If we combined the medium and large companies, then their response rate would be equal to that of the small companies.

An experiment was conducted to investigate the effect of a new weed killer to prevent weed growth in onion crops. Two chemicals were used: the stan-dard weed killer (S) and the new chemical (N). Both chemicals were tested at high and low concentra-tions on 50 test plots. The percent of weeds that grew in each plot was recorded. Here are some boxplots of the results.

Which of the following is not a correct statement about the results of this experiment?

• At both high and low concentrations, the new chemical results in better weed control than the standard weed killer.

• For both chemicals, a smaller percentage of weeds typi-cally grew at higher concentrations than at lower concentrations.

• The results for the standard weed killer are less variable than those for the new chemical.

• High and low concentrations of either chemical have approximately the same effects on weed growth.

• Some of the results for the low concentration of weed killer show a smaller percentage of weeds growing than some of the results for the high concentration.