week 12

a table was used for this question With the following data we can say that we have (in our sample) accounted for 50% of the variance in coping by our explanatory variables (problem solving and motivation). True or false? a. predictors (constant), problem, motivation

True

a table was used for this question You are interested in whether problem solving ability can predict the ability to cope well in difficult situations. You also would like to look at whether motivation can predict coping. It may be that these two factors together predict coping even better. You produce the following initial data. a. predictors (constant), problem, motivation As a result we can say that the correlation between coping and both of the explanatory variables (problem solving and motivation) is 0.71. True or false?

True

Match the letters in the regression equation to their correct descriptions. b

Value of the slope of the line.

Match the letters in the regression equation to their correct descriptions. y

Variable to be predicted.

a table was used for this question From the following what is the value of the slope of the line? a. dependent variable music ability

-.633

Match the letters in the regression equation to their correct descriptions. x

. Score on the predictor variable.

Using some fictitious data we wish to predict the musical ability for a person who scores 8 on a test for mathematical ability. We know the relationship is positive. We know that the slope is 1.63 and the intercept is 8.41. What is their predicted score on musical ability?

21.45

Consider this fictitious data that you might see in some linear regression output. a. dependent variable music ability a Table was used for this

8.425

In the data above in Q5 the t value for sport ability was 5.83 and the associated probability is 0.000. Which of the following is most appropriate?

< 0.001

Which of the following is an incorrect statement?

A researcher is interested in performing a multiple regression using 5 explanatory variables. He is interested in the overall R2 and the significance of each variable separately. According to Tabachnick and Fidell he needs 90 participants.

We have a negative relationship between number of drinks consumed and number of marks in a driving test. One individual scores 3 on number of drinks consumed, another individual scores 5 on number of drinks consumed. What will be their respective scores on the driving test if the intercept is 18 and the slope is -3?

Driving test scores (y-axis) will be 9 [individual who scored 3 on drink consumption] and 3 [individual who scored 5 on drink consumption]. y = a - bx [the minus sign = negative relationship] y [predicted driving score] = a [intercept] - b [slope] x X [known score on consuming alcohol] y = 18 - (3 x 3) y = 18 - (9) y = 9 [individual who scored 3 on drink consumption] y = 18 - (3 x 5) y = 18 - 15 y = 3 [individual who scored 5 on drink consumption ]

If you read that the slope of a scattergram is 2.00, what does this mean?

For every increase of 1 on the x-axis there is an increase of 2.00 on the y-axis.

Which of the following is incorrect?

In linear regression the line of best fit maximises the distance between the scores and the regression line.

a table was used for this question Examine the following fictitious data. Which of the following statements can we not say?

In order to obtain a measure of explained variance you need to square the adjusted R-square.

Match the letters in the regression equation to their correct descriptions. a

Intercept, or place where the line intercepts the y axis.

Linear regression can achieve which of the following?

Predict someone's statistical grade from their mathematical ability. Allow us to predict that as the weather gets 30% colder then the sales of scarves will increase by 50%. Identify how much variable y will change if variable x changes.

a table was used for this question Using the correct value for the slope of the line from the following what does this mean? a. dependent variable music ability

The slope of the line (b) is -.633. This means that for every increase of 1 on the x-axis (sport ability) the score on the y-axis drops by .633.

a table was used for this question You are interested in whether problem solving ability can predict the ability to cope well in difficult situations; whether motivation can predict coping and whether these two factors together predict coping even better. You produce the following results. a. dependent variable coping skills in difficult situations Which of the following statements is incorrect?

The t value for problem solving is 2.082 and the associated probability is .03. This tells us the likelihood of such a result arising by sampling error, assuming the null hypothesis is true, is 97 in 100.

Linear regression means that every time the value of x increases, y changes by a constant amount.

True

a table was used for this question In addition to this data we have some confidence intervals. What can we say about the 95% confidence interval for the intercept? a. dependent variable music ability

We can be 95% confident that the intercept of our population can be found within the interval 6.753 to 10.097.

If b = 0 the line of best fit will conventionally be drawn ______.

as horizontal.

The slope of the line is called:

b and gives us a measure of how much y changes as x changes.

The variable being predicted is called the:

criterion or y variable.