Unit 11 Review

At the end of the month, a restaurant manager used the total food sales for the month and the total number of customers for the month to calculate that the mean amount spent per customer during that month was $12.59. Is this value a statistic or a parameter? Explain.

• Statistic because it only gives a sample of the yearly income despite using every customer during the month.

• Parameter because it involves the entire population of the restaurant's customers during that month and because the restaurant wanted to know only about that one month.

• Parameter because it is likely that the income is nearly steady from month to month.

• Statistic because it involves quantities that are likely to change from one month to the next.

Which is a statistical question that uses a categorical variable?

• What is your favorite primary color?

• How much do you spend on groceries each month?

• How much change do you have in your pocket?

• How many words do you actively use on average?

Which of the following is a statistical question that uses a quantitative variable?

• What is your favorite class?

• What is your hourly wage?

• What is the tallest building in Chicago?

• What types of pets do you own?

Why is the following a statistical question?

"How many minutes did students spend reading books last night?"

• Some students might not have read a book last night.

• The question asks about only one night.

• Some students might have read more than one book last night.

• Some students could have spent more time than others reading books.

Which description(s) are populations? Select all that apply.

• the number of children in one household in the town

• the number of children in all households of a neighborhood in the town

• the number of children in all households in the town

• the number of children in every other household on a street in the town

The data were collected from all race participants to answer the question, "What is the average age of runners in the Fall Harvest 5K?" Does this histogram represent data related to a parameter or statistic?

• Statistic because the median and average are close together

• Parameter because it represents data collected from the entire population of racers

• Parameter because the age of racers is unlikely to change drastically.

What statistical question could have been asked to collect the data shown in the dot plot?

• How many minutes did you spend reading yesterday?

• How many minutes are in an hour?

• Did anybody in the class spend time reading yesterday?

If the data in the dot plot shows how many minutes students spent reading yesterday, how many hours in all did these students spend reading? _______ hours

The plants in your​ neighbor's garden are in the repeated order of tulip​s, dandelion​s, lilac​s, and roses. You decide to take a systematic sample using an interval of 5 ​plants, starting from the first plant. Using your systematic​ sample, you estimate that of the 60 plants in his ​garden, 15 are lilacs. How accurate is your​ estimate? Explain.

• The estimate is not accurate. The pattern in the plants introduces a bias in the sample, so it is not representative of the population.

• The estimate is not accurate. The pattern in the plants does not introduce any bias in the sample, so it is not representative of the population.

• The estimate should be fairly accurate. The pattern in the plants does not introduce any bias in the sample, so it should be representative of the population.

• The estimate should be fairly accurate. The pattern in the plants does not introduce any bias in the sample, so it is not representative of the population.

A researcher wants to know the average growth of a certain plant one week after germination. The greenhouse where he grows the plants has 12 trays with 36 plants on each tray. He picks one tray from the greenhouse and measures the heights of each plant. The results are shown in the dot plot. When analyzing the​data, he sees that the heights of the plants are clustered around 2 in. Could this be the result of bias in his sampling​ method? Explain.

• Yes, he could only gather information about 36 plants, which is not enough to eliminate bias.

• Yes, he sampled plants from only one tray, so the sample is not random.

• No, he chose a random sample from among the 12 trays.

• No, although he chose which tray to look at, there are 36 plants on the tray, which is a large enough sample to eliminate any bias in the results.