CH 3, 3-3 Measures of Relative Standing and Boxplots

Question 1

What is the number of standard deviations that a given value x is above or below the mean?

Answer 1

z number

Question 2

What is the formula for finding a z score?

Answer 2

Question 3

What are the round off rules for z scores?

Answer 3

two decimal places

Question 4

What determines is a z score is significantly low or significantly high?

Answer 4

less than or equal to -2 values are signficantly low

greater than or equal to +2 values are significantly high

Question 5

What are measrues of location denoted with P₁, P₂, …, P₉₉, which divide a set of data into 100 groups with about 1% of the values in each group?

Answer 5

Percentiles

Question 6

What is the formula for finding the percentile of a data value?

Answer 6

= (number of values less than x / total number of values) * 100

Question 7

What formula converts a percentile to a data value?

Answer 7

Question 8

What are measures of location, denoted Q₁, Q₂, and Q₃, which divide a set of data into four groups with about 25% of the values in each group?

Answer 8

Quartiles

Question 9

In which quartile is at least 75% of the stored values less than or equal to said quaritle and 25% fo the values are greater?

Answer 9

Q₃

Question 10

What five values does the 5-number summary consist of?

Answer 10

Minimum

Q₁

Q₂

Q₃

Maximum

Question 11

What is a graph of a data set that consitis of a line extending from the mimimum value to the maximum value and a box with lines drawn at the fist quartile, the median, and the third quartile?

Answer 11

boxplot or box-and-whisker diagram

Question 12

How do you calculate the interquartile range? (IQR)

Answer 12

IQR = Q₃ - Q₁

Question 13

What are the steps in identifying an Outlier for Modifiied Boxplots?

Answer 13

Find Q₁ Q₂ Q₃

Find the IQR

Evaluate 1.5 * IQR

Value is an outlier if it is above Q₃ by an amount greater than 1.5 * IQR

Or bellow Q₁ by an amount greater than 1.5 * IQR