Statistics Midterm Review

The percentile represents the....

• percent of data values that are below.
• percent of data values that are above.
• number of data values that are below.
• number of data values that are below.

The mean temperature in Glens Falls for the month of February is 23 degrees with a standard deviation of 4.2 degrees.  What is the z-score for a temperature of 17 degrees?  

• 1 
• 1.43
• -1.43
• 11.5

The shelf life of a particular dairy product is normally distributed with a mean of 12 days and a standard deviation of 3 days.

About what percent of the products last between 12 and 15 days?

• 68%
• 34%
• 16%
• 2.5%

The most important advantage of experiments over observational studies is that

• A) experiments are usually easier to carry out
• B)Experiments can usually give better evidence of causation
• C) Confounding cannot happen in experiments
• D) Observational studies cannot use random samples

Use the 1.5 IQR rule to determine if there are any outliers for the following numbers:
84, 88, 72, 74, 98, 16, 94 

• Yes, 16 is an outlier.
• Yes, 33 is an outlier.
• Yes, 98 is an outlier.
• There are no numbers less than 39 or greater than 124, therefore there are no outliers.

What is the probability that the person picked will be a boy given they speak German?

• .727

• .4

• .161

• .225

Which answer shows categorical data?

• Age
• Height
• Number of cousins
• Favorite singer

What percent of data lies within 1 standard deviation from the mean?

• 95%

• 99%

• 68%

• 100%

You draw two marbles at random from a jar that has 20 red marbles and 30 black marbles without replacement.  What is the probability that both marbles are red?

• 0.1551
• 0.1600
• 0.2222
• 0.4444

Descriptive statistics involves...

• collection, presentation, and description of sample data

• the technique of interpreting the values resulting from the descriptive techniques and making decisions and drawing conclusions about the population

• attempting to provide incorrect information and provide misleading graphs

• using information, numbers, and graphics even when data can't be collected