Comparing Samples

The means and mean absolute deviations of Sidney’s and Phil’s grades are shown in the table above.

Which expression represents the ratio of the difference of the two means to Sidney’s mean absolute deviation?

The means and mean absolute deviations of the amount of rain that fell each day in a local city, last week and this week, are shown above.

Which expression compares the difference of the two means to this week’s mean absolute deviation?

Jillian and Dawn are playing a game of miniature golf. In this game, the score on a hole is the number of putts it takes to get the ball into the hole. The winner is the player with the lowest score. After playing 18 holes, Jillian’s mean is 2.4 and Dawn’s mean is 3.3. Which explains who won the game?

• Jillian won the game because her score varied less than Dawn’s score.

• Jillian won the game because the person with the lower mean took fewer putts on average for each hole.

• Dawn won the game because the person with the greater mean played better.

• Dawn won the game because her mean absolute deviation was less than Jillian’s.

Two months ago, the mean daily rainfall in a local city was 9.4 cm. The mean absolute deviation was 3.5 cm. Last month, the mean daily rainfall in that city was 11.5 cm, and the mean absolute deviation was 1.6 cm.

Which statement about the rainfall is true?

• More rain fell two months ago than last month.

• About the same amount of rain fell two months ago as last month.

• Last month, the amount of rain that fell each day varied about the same as the month before.

• Last month, the amount of rain that fell each day varied less than the month before.

Plot A shows the number of hours ten girls watched television over a one-week period. Plot B shows the number of hours ten boys watched television over the same period of time.

Which statement compares the shape of the dot plots?

• There is a gap in both plots.

• There is a gap in Plot A, but not in Plot B.

• The data is spread widely across both plots.

• The data is spread widely across Plot B, but not across Plot A.

Which statement compares the shape of the two dot plots?

• There is a gap in both plots.

• There is a gap in Anika’s scores, but not in Lorenzo’s scores.

• The data is widely spread across both plots.

• The data is more widely spread for Lorenzo’s scores than for Anika’s.

Which is a true statement for most of the data in each plot?

• Most of the data in each plot are greater than 48.

• Most of the data in each plot are less than 48.

• Most of the data in each plot are around 52.

• Most of the data in each plot are around 54.

When comparing the two sets of data, which is a true statement?

• There are gaps in both sets of data.

• The ranges are the same.

• The two sets of data do not overlap.

• The rainfall peaks at a lower value in the Lowlands.

Myra polled twenty-five students in her class to determine the number of movies the students attended at the theater this year. The results are in the table. She decided to find the mean of a sample using Row 1 and Row 5.

What is the mean of her sample?

• 2

• 4

• 6

• 8

Ms. Sanchez’s students were asked how many hours they spend participating in organized sports each week. Each row of the table represents one sample from the class.

What is the mean of the sample in the third row?

• 2..2

• 2.8

• 3

• 3.4