Stats 101 Refresher

Which statements are true? The bigger the standard deviation the …

• bigger the mean.

• • more people differ in their answers.

• • bigger the variance.

• • closer to the mean are most values.

Rank the different scale levels according to the amount of information they contain. Start with the scale level with the least amount of information.   
- Ordinal (O)
- Nominal (N)
- Ratio (R)

- Interval (I)

(a)  

Tags

CCSS.6.SP.A.2

A z-score of -3.0 means:

• • that the score is below the sample mean.

• • that the mean is three standard deviations below the particular score.

• that there is a mistake in your calculation.

• that you have too few decimal places.

Which of the following is the best definition of standard deviation?

• • The average of the sum of squared deviations from the mean.

• • The typical amount by which scores differ from the mean of a set of scores.

• • The average of a set of scores.

• The mean squared deviation from the average.

If you have nominal data which are meaningful statistics?

• • percentage frequencies.

• • percentiles.

• • frequencies.

• • mean.

Tags

CCSS.6.SP.B.5A

5.  Which statements are true for the following scatter plot?

• • The relationship is positive. 

• • There is a person who scored highest in both tests.

• • Fluid intelligence causes knowledge.

• The higher the fluid intelligence the bigger the knowledge.

Tags

CCSS.8.SP.A.1

You have found a correlation of r = -.80 between a person’s focused attention ability and the number of traffic accidents he or she causes. Which statements are true?

• • The relationship is large.

• • A low focused attention ability goes along with more accidents.

• • A correlation of -.42 is exactly half as much.

• • The determination coefficient is 64%.

Tags

CCSS.8.SP.A.3

What is a residual in linear regression?

• difference between observed and predicted score.

• explained amount of variance.

• difference between the variance of the observed values and the variance of the expected values.

• difference between independent variable (X) and dependent variable (Y).

Tags

CCSS.HSS.ID.B.6B

The multiple R in multiple regression analysis is:

• • the amount of criterion variance attributable to the predictors.

• the correlation between the predicted and the observed values.

• • the correlation between the predicted values and the residuals.

• • the amount of shared variance among the predictors.

Tags

CCSS.HSS.ID.B.6B

A study was conducted to examine the relationship between learning time per day in hours (X) and scores (on a 40 point scale) on the final test (Y) in statistics. The sample linear regression is . From this we can say that: 

• • A one hour increase in learning per day increases the predicted score by 0.8.

• • A one hour increase in learning per day decreases the predicted score by 0.8.

• A one hour increase in learning per day increases the predicted score by 6.

• • Learning 6 hours per day increases the predicted score by 0.8.

• • The predicted score for students learning zero hours is 6.

Tags

CCSS.HSF.LE.B.5