Which data is from a sample and not a population?

Select all that apply.

• The exit poll predicts Candidate A will win.

• 78% of students were at the basketball game.

• The median age of residents in the town is 47.

• 55% of Faye’s class bought lunch today.

• The average grade point average of students attending State University is 2.53.

Happy Pets Boarding is interested in how many of their customers purchase a grooming package when they board their pets. They selected a random sample of 25 customers picking their pets up on Friday. They determined that 38% of the customers purchased a grooming package when they boarded their pets.

Which statement about Happy Pets Boarding is true?

• The sample is the percentage of customers who also purchase grooming.

• The sample is too small to make generalizations about the population.

• The sample might not be representative of the population since it only includes customers from one day.

• The sample shows that exactly 38% of customers purchase a grooming package when boarding their pets.

Which data is from a sample that can support valid inferences?

Select all that apply.

• The mean amount spent by the first 10 customers to make a purchase at a new store.

• Heads results from 50% of coin tosses based on 25 coin tosses.

• Baseball player’s batting average of .231 after the first game.

• Mean run time from first 25 students to finish in gym class.

• Median run time from every 10th student in line in gym class.

Three students investigated the average time it took students to travel to school in the morning. Each student randomly selected 100 students. The mean time from their sample is shown in the table below. Which statement is true based on data?

• The mean travel time of all of the students is probably between 21 and 25 minutes.

• The mean travel time of all of the students is exactly 23 minutes.

• The mean travel time of all of the students cannot be greater than 25.3 minutes.

• The mean travel time of all of the students cannot be less than 21.5 minutes.

The table below shows the percentage of students who selected a favorite lunch entrée from a random sample of all students.

Which entrée is most likely to be the favorite entrée of the population of all students? Why?

• Hamburger/Cheeseburger is most likely to be the favorite entrée since it received the highest percentage from the random sample.

• Pizza is most likely to be the favorite entrée since it received the highest percentage from the random sample.

• Salad is most likely to be the favorite entrée since it received the highest percentage from the random sample.

• Tacos is most likely to be the favorite entrée since it received the highest percentage from the random sample.

The table below shows the percentage of students who selected a favorite lunch entrée from a random sample of all students.

Which entrée is most likely to be the least favorite entrée of the population of all students? Why?

• Hamburger/Cheeseburger is most likely to be the least favorite entrée since it received the lowest percentage from the random sample.

• Pizza is most likely to be the least favorite entrée since it received the lowest percentage from the random sample.

• Salad is most likely to be the least favorite entrée since it received the lowest percentage from the random sample.

• Tacos is most likely to be the least favorite entrée since it received the lowest percentage from the random sample.

20 students randomly surveyed groups of 25 people asking how many times per week they eat out. The dot plot below shows the average number for each group surveyed. If another group of 25 people were randomly selected, in what range will the mean most likely be?

• 3 – 5

• 3 – 7

• 7 – 9

• 7 – 10

Sample groups of students were asked if candy should be removed from the vending machines at school. 25 randomly selected groups of 15 students were asked this question. Here is a dot plot of the proportion of students who agreed with removing the candy from the vending machines. If the actual population proportion is 28% that agree with removing the candy, does this match the dot plot from the samples? Why or why not?

• The dot plot matches the actual population proportion, since the results cluster between 0.2 and 0.3

• The dot plot does not matches the actual population proportion, since the results show greater than .5

• The dot plot does not matches the actual population proportion, since the results do not show .28

• The dot plot matches the actual population proportion, since the results have the most at 0.3

10 randomly selected pet owners and non-pet owners were asked how much time they spent, in minutes, walking each week. The data is shown in the table below. Comparing the data from both groups, which group spends more time walking?

• Non-pet owners

• Pet owners

• Both groups are equal

• Cannot be determined

10 randomly selected pet owners and non-pet owners were asked how much time they spent, in minutes, walking each week. The data is shown in the table. Is there a meaningful difference between the centers of the two groups as measured by their variability?

• No, the difference in the means is less than the variability.

• No, the difference in the means is greater than the variability.

• Yes, the difference in the means is less than the variability.

• Yes, the difference in the means is greater than the variability.