Standard deviation Practice quiz

The standard deviation of a set of data is calculated by:

• • Adding all the data points and dividing by the number of data points.

• • Finding the difference between each data point and the mean, squaring the differences, adding them up, and dividing by the number of data points minus one.

• Multiplying all the data points and taking the square root.

• • Finding the difference between the largest and smallest data points.

A standard deviation of 0 means that:

• The data set has a high variability.

• All values in the data set are the same

• The range of the data is very low

• The data set has a low variability.

A standard deviation of 10 means that:

• The data points in a dataset are, on average, 5 units away from the mean.
• The data points in a dataset are, on average, 15 units away from the mean.
• The data points in a dataset are, on average, 20 units away from the mean.
• The data points in a dataset are, on average, 10 units away from the mean.

Two data sets have the same mean, but one data set has a larger standard deviation than the other. This means that the data set with the larger standard deviation is:

• more spread out
• more precise.
• more consistent.
• The same as the data set with the smaller standard deviation.

Which of the following is the best measure of the spread of a dataset?

• standard deviation
• range
• mean
• median

All of the below sets have the same mean.
Set 1-Standard Deviation=3.1
Set 2-Standard Deviation=4.9
Set 3-Standard Deviation=1.7
Set 4-Standard Deviation=3.2
Which set of data probably has the points closest to the mean?

• 1
• 2
• 3
• 4

The distribution of annual salaries for the 21 employees in a small company has a median of $45,000 and a standard deviation of $10,000. The owner of the company promotes one of the employees and the employee’s salary increases from $65,000 a year to $95,000 a year. What impact will this salary increase have on the median and the standard deviation of annual salaries for this company? 

• Both the median salary and the standard deviation will change. 
• Neither the median salary nor the standard deviation will change. 
• The median salary will increase, but the standard deviation will not change. 
• The median salary will not change, while the standard deviation will increase. 

Which of the following is a measure of spread, or variability?

(select all that apply)

• Interquartile Range

• Standard Deviation

• Mean

• Median

• Range

What does standard deviation represent?

• How many different variations are in the data set.

• How the population varies compared to the sample.

• How spread out each data value is from the mean.

• The range, but with a bunch of other stuff going on.

The table on the right shows the statistics for the number of hours of homework per night during Term 1 and Term 2 for a group of students. What must be true?

• Term 1 students spent less time on homework than Term 2, but there was more variation in the number of hours spent on the homework.

• Term 2 students spent less time on homework than Term 1, but there was more variation in the number of hours spent on the homework.

• Term 1 students spent less time on homework than Term 2, but there was less variation in the number of hours spent on the homework.

• Term 2 students spent less time on homework than Term 1, but there was less variation in the number of hours spent on the homework.