Quantitative Analysis Quiz 2

If the correlation coefficient (r) = 1.00, then

all the data points must fall exactly on a straight line with a positive slope.

In its standardized form, the normal distribution

has a mean of 0 and a standard deviation of 1.

If the correlation coefficient (r) = 1.00, then

there is no unexplained variation.

The probability that a standard normal variable Z is positive is ________.

.5

Suppose Z has a standard normal distribution with a mean of 0 and standard deviation of 1. The probability that Z is less than -2.20 is ________.

0.14

A company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. Suppose the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 3.5 years. What proportion of the plan recipients would receive payments beyond age 75?

0.23

For some positive value of Z, the probability that a standard normal variable is between 0 and Z is 0.3340. The value of Z is:

0.97

The Y-intercept (b0) represents the

predicted value of Y when X = 0.

For some value of Z, the probability that a standard normal variable is below Z is 0.2090. The value of Z is:

- 0.81

You were told that the mean score on a statistics exam is 75 with the scores normally distributed.The standard deviation is 10. What percentage of students will score over 95?

2.28 %

Given that X is a normally distributed random variable with a mean of 50 and a standard deviation of 2, , If Z value for a given value of X is -2; What is the value of X?

46

You were told that the mean score on a statistics exam is 75 with the scores normally distributed. The standard deviation is 10. Between what 2 scores will 68.2 % of the students scores be located?

65 and 85

A company that sells annuities must base the annual payout on the probability distribution of the length of life of the participants in the plan. Suppose the probability distribution of the lifetimes of the participants is approximately a normal distribution with a mean of 68 years and a standard deviation of 3.5 years. Find the age at which payments have ceased for approximately 86% of the plan participants.

71.78

True or False: The value of r is always positive.

False

True or False: Regression analysis is used for prediction, while correlation analysis is used to measure the strength of the association between two numerical variables.

True

True or False: Theoretically, the mean, median, and the mode are all equal for a normal distribution.

True

True or False: When r = -1, it indicates a perfect relationship between X and Y.

True

The strength of the linear relationship between two numerical variables may be measured by the

coefficient of correlation.

The slope (b1) represents

the estimated average change in Y per unit change in X.

Assuming a linear relationship between X and Y, if the coefficient of correlation (r) equals -0.30,

the slope is negative.

In performing a regression analysis involving two numerical variables, we are assuming

the variation around the line of regression is the same for each X value.

The standard error of the estimate is a measure of

the variation around the sample regression line.