REVIEW ON STATISTICS

1. Suppose that an engineer is designing a nylon connector to be used in an automotive engine application. Eight prototype units are produced and their pull-off forces measured, resulting in the following data (in pounds):

12.6, 12.9, 13.4, 12.3, 13.6, 13.5, 12.6, 13.1

Find the mean and the mode for this sample.

• 13.4, 12.6

• 13, 12.4

• 13, 12.6

• 13.6, 12

A researcher studies the factors that determine the number of children future couples decide to have. The variable ‘number of children’ is a

• Continuous variable

• Discrete variable

• Categorical variable

• Ordinal variable

What is the variance for the following set of scores: 2, 2, 2, 2, 2.

• 4

• 2

• 0

• 25

What is the approximate shape of the distribution?

• Nearly symmetric.

• Skewed to the left.

• Skewed to the right.

• Bimodal (has more than one peak).

Which one of these statistics is unaffected by outliers?

• Mean

• Interquartile range

• Standard deviation

• Range

Using the box plot provided, what is the vertical line circled in red?

• Quartile 1

• Quartile 2

• Quartile 3

• Interquartile Range

Pick the choice that best completes the following sentence. If a relationship between two variables is called statistically significant, it means the investigators think the variables are

• related in the population represented by the sample.

• not related in the population represented by the sample.

• related in the sample due to chance alone.

• very important.

What is the correct decision in a hypothesis if the data produce a t-statistic that is in the critical region?

• Reject H0

• Fail to reject H0

• Reject H1

• Fail to reject H1

Using the box plot provided, what is the rectangle circled in red?

• Quartile 1

• Quartile 2

• Quartile 3

• Interquartile Range

Calculate the mean number of children per family for the sample from the following table.

• 1.91

• 2.47

• 3.14

• 2.19