Center and Spread of Data

• only 2nd period is symmetric
• both plots are symmetric
• 5th period is bimodal
• 2nd period's center is higher than 5th period

• the spread of 5th period is greater than 2nd period
• the spread of 2nd period is greater than 5th period
• 5th period is skewed right

• 2nd period has a gap at 16
• 5th period has an outlier
• 5th period's center is higher than 2nd period
• 2nd period's spread is greater than 5th period's spread

• only Hayes Road is symmetric
• Hayes Road's center is at 60
• Jefferson Road's center is at 55
• only Jefferson Road is symmetric

What measure of center is best to use when we have outliers?

• mean

• median

• mode

• range

Which measure of spread should be used to describe the distribution?

• standard deviation

• interquartile range

• range

• median

What does the interquartile range (IQR) measure?

• The range of the entire data set

• The spread of the middle 50% of the data

• The average value of the data set

• The difference between the mean and median

Which summary statistic should be used to compare the two data sets and why?

• The median and the interquartile range because they are normally distributed.

• The median and the interquartile range because they are skewed.

• The mean and the standard deviation because they are normally distributed.

• The mean and the standard deviation because they are skewed.

A class scored 83,83,87,87,88,88,91,94,95,96,98,100,100 on a test, but then a student scored a 28.

The mean will ​ (a)  

The median will ​ (b)  

The ​ (c)   is the best measure of center for this data.

• decrease

• increase

• stay the same

• go up

• go down

• median

• mean

Describe the shape of the graph.

• Skewed right

• Skewed left

• Uniform

• Symmetrical