Stats Final Exam Review

What is the interquartile range (IQR)?

• 4
• 64
• 60
• 8

At an assembly 7 out of 10 students who entered the gym were carrying a backpack. Based on this information, if 700 students were at the assembly, how many students could be expected to be carrying a backpack?

• 49

• 490

• 210

• 421

A researcher has gathered data about the number of soft drinks teenagers drink on a daily basis by taking a random sample of 1500 teenagers from around the world. We find that our data shows that the mean is larger than the median. What does this tell us about the shape of the distribution?

• skewed right

• skewed left

• uniform

• symmetric

To find out the color preference of residents at a local retirement community, the president asks each of the residents what their favorite color is. What type of variable is this?

• Quantitative

• Dimensional

• Categorical

• Quasimodal

The "Emperical Rule" states that the normal distribution contains 99.7% of the data between how many standard deviations?

• 3

• 1

• 2

• 10

How would you describe this graph? 

• Symmetric
• Skewed Right
• Skewed Left
• Bimodal

The five number summary for a one-variable dataset is {5, 28, 29, 42, 75}. If you wanted to construct a modified boxplot for the dataset (that is, one that would show outliers if there are any), what would be the maximum possible length of the right side “whisker”?

• 21
• 42
• 33
• 14

A slice of pizza from a certain restaurant has an average area of 40 square inches with a standard deviation of  5 square inches.  Assuming the distribution of areas is approximately normal, what proportion of slices will be between 35 and 50 square inches

• 68%
• 34%
• 81.5%
• 95%

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 1990’s was 470 and the standard deviation was 110.  In 2009, the mean was 515 and the standard deviation was 116.  

 What is the standardized score (z-score) for a student who scored 530 on the old SAT scale? 

• 0.55
• -0.55
• 525.73
• 0.13

High school textbooks don't last forever. The lifespan of all high school statistics textbooks is approximately Normally distributed with a mean of 9 years and a standard deviation of 2.5 years.  What percentage of books last more than 10 years? 

• 11.5%
• 34.5% 
• 65.5%
• 69%