Draw Inferences Using Data

In an effort to try to convince her mother that she is too old to join the intermediate swim​ class, Mira, who is 13 years​ old, gathers data on the ages of a random sample of members of the current intermediate swim class. The results of the data collected by Mira are displayed in the dot plot shown.

• It is likely that she will be able to convince her mother.​ Mira's age is within the area where the data are clustered.

• It is likely that she will be able to convince her mother.​ Mira's age is to the left of the area where the data are clustered.

• It is unlikely that she will be able to convince her mother.​ Mira's age is within the area where the data are clustered.

• It is unlikely that she will be able to convince her mother.​ Mira's age is to the left of the area where the data are clustered.

The following dot plots show the amount of time it takes each​ person, in a random​ sample, to complete two similar problems. Make a comparative inference about the two problems.

• The problems are equally challenging.

• Problem 2 is more difficult because it took students longer on average.

• Problem 1 is more difficult because it took students longer on average.

The following shows the number of calls two radio shows get each day for a ten day period. The two shows are on at the same time. Make a comparative inference based on the median values.

• Show 1 usually receives more calls.

• Show 2 usually receives more calls.

• The shows usually receive equal numbers of calls.

• There is not enough data to draw an inference.

A random survey of 7th graders finds that 7 out of 10 have more than 1 hour of screen time each day. If there are 110 7th graders in your school, how many would you expect to have more than 1 hour of screen time?

• 77

• 70

• 75

• 81

A travel club has 3,000 members. A random sample of 50 of the club members found that 12 people like mountain vacations best. Which statement is NOT supported by the sample data?

• Twenty-four percent of those sampled say they like mountain vacations best.

• An estimated 720 club members would likely say they enjoy mountain vacations best.

• Almost one-quarter of club members would likely say they enjoy mountain vacations best.

• More than 2,500 club members would likely say they prefer other vacations over mountain vacations.

What inference can you draw from this survey?

• I can infer that most students in this school like pizza.

• I can infer that very few students like hamburgers.

• I can infer that their favorite is corn dogs.

• I can infer that most students in this school like hamburgers.

How can sample data be used to form an estimate about the population?

• A proportion can be solved to relate the sample to the population.

• A proportion can be solved to relate the sample to the mean.

• A proportion can be solved to relate the sample to the median.

• You cannot make an estimation from sample data.

Sonya randomly surveys 26 seventh graders to gather data about the amount of time spent each week using the Internet. Sonya records the data in the dot plot shown. What is the median of the data set?

• 7

• 7.5

• 8

• 7.25

A valid sample shows that 3 of 20 players win at a carnival game. If 275 people play the game each day, how many winners would you expect to have?

• about 50

• about 45

• about 41

• about 36

3 of 5 doctors surveyed by a pharmaceutical company prefer their new Brand X medicine compared to the other leading brand. Is this a valid inference?

• Yes they randomly chose doctors for the survey.

• No there is no evidence that they chose the doctors for the survey at random.

• Yes they chose doctors they knew would prefer their Brand X.

• No they randomly chose doctors for the survey.