Transforming Data

The mean test score for a class was 76 with a standard deviation of 5 points, and the shape was skewed left. The teacher decides to add 4 points to every students test score. What is the new mean, standard deviation, and shape for the distribution of test scores?

• mean=80, SD=5, shape is skewed left

• mean=80, SD=9, shape is skewed left

• mean=80, SD=5, shape is more skewed left

• mean=80, SD=9, shape is approx. symmetric

A 50 point test had a mean of 42 with a standard deviation of 5 points. The original shape of the distribution of test scores was approximately symmetric. The teacher decides to multiply all scores by 2 (so the total is out of 100). What is the new mean, standard deviation and shape for the distribution of test scores?

• mean=84, SD=10, approx. symmetric

• mean=84, SD=5, approx. symmetric

• mean=42, SD=5, approx. symmetric

• mean=84, SD=10, slightly skewed right

If 30 is added to every observation in a data set, the only one of the following that is not changed is

• the mean

• the 75th percentile

• the median

• the standard deviation

• the minimum

SELECT ALL that will change if you multiply all of the data by a constant

• mean

• median

• range

• IQR

• standard deviation

A data set currently has a mean of 69.168, sd of 3.20, min of 61.5, Q1 of 67.75, median of 69.5, q3 of 71 and a max of 74.5. If every value in the data is divided by 100, what is the new IQR?

Coach Ferguson uses a thermometer to measure the temperature (in degrees C) at 20 different locations in the school swimming pool. An analysis of this yields a mean of 25 C and a sd of 2 C. Find the sd of the temperature in Farenheit. Note that F=(9/5)C+32

Tags

CCSS.8.EE.C.7B

A 50 point test had a mean score of 39 with a standard deviation of 4 points. The original shape of the distribution of test scores was approximately symmetric. The teacher decides to multiply all scores by 2 (so the total is out of 100) and then also add 3 points. What is the new mean, standard deviation and shape for the distribution of test scores?

• mean=81, SD=8, approx. symmetric

• mean=81, SD=11, approx. symmetric

• mean=78, SD=8, approx. symmetric

• mean=81, SD=4, approx. symmetric

For which option below would the shape of a distribution change?

• Adding transformations

• Multiplying transformations

• Shape never changes

• Logarithm transformations

Fill in the Blanks: Multiplying a constant to every data value ______ (to) measures of center/position and _________ (to) measures of spread.

• multiplies, multiplies

• multiplies, doesn't affect

• doesn't affect, multiplies

• doesn't affect, doesn't affect

The average on the Unit 1 test is 85 with a standard deviation of 10. Ms Lightbody (almost Maynard) adds ten points to everyone's score. What is the new mean?

• 95

• 85

• 20

• 10