Chapter 2 Introduction Statistics Graphs, Charts and Data

Forty students took a statisitics exam having a maximum of 50 points. The distribution of scores is given in the stem and leaf plot.

Tess's score was 25. What was her percentile?

• 12th

• 30th

• 35th

• 70th

Which of the following Statements about this distribution can be concluded from the graph?

• The distribution is left-skewed

• The median is between $10 and $20

• The standard deviation of the distribution is more than $60

• The mean is less than the median.

Until the scale was changed in 1995, SAT scores were based on a scale set many years ago. For Math scores the mean under the old scale in the 1990s was 470 and the standard deviation was 110. In 2013, the mean was 515 and the standard deviation was 116. Gina took the SAT in 1994, ans scored 500 on the Math test, Her cousin Colleen took the SAT in 2013 and scored 530 on the Math test. Who did better relative to their peers, and how can you tell?

• Colleen-She scored 30 points higher than Gina

• Colleen-her standardized (z) score is higher than gina's

• Gina- her standaridized (z) score is higher than Colleen's

• Gina-the Standard deviation was bigger in 2013.

The dotplots show the lifetimes of several Brand X and Brand Y batteries.

What Percentage of all the batteries (both brands) lasted more than 42 hours?

• 43.3%

• 56.7%

• .433%

• .567%

The dotplots show the lifetimes of several Brand X and Brand Y batteries.

Give a reason someone might prefer a Brand X battery.

• Because of the high outliers

• Because the data is less spread, making it more predictable.

• Because the majority of Brand X's data is above the majority of Brand Y's Data

• Because brand Y is more expensive.

The dotplots show the lifetimes of several Brand X and Brand Y batteries.

Give a reason someone might prefer a Brand Y battery.

• Because Brand X is more expensive.

• Because the majority of Brand Y's data is above the majority of Brand X's data, and the lower outliers seem rare.

• Because Brand Y is cheaper.

• Because they Prefer Pokemon Y over Pokemon X.

15a: At what percentile does a student who used her computer for 7 hours last week fall? (closest guess)

• 55th Percentile

• 57th Percentile

• 65th Percentile

• 60th Percentile

15b: Estimate the Interquartile Range (IQR) from the graph. (closest guess)

• Q1=3, Q3=11, IQR=8

• Q1=3, Q3=12, IQR=9

• Q1=3, Q3=10, IQR=7

• Q1=2, Q3=11, IQR=9

A data distribution has Q1=20, Q3=32. Would the data x=51 be an outlier? (Use the 1.5 IQR rule)

• Yes

• No