Q: Which formula is used to calculate the expected count for a cell in a contingency table when performing a Chi-Square Test for Independence?

$$\frac{\text{Row Total} \times \text{Column Total}}{\text{Grand Total}}$$

Q: Which Excel function is used to calculate the p-value for a Chi-Square Test Statistic?

$$\text{CHISQ.DIST.RT(\text{test statistic}, \text{degrees of freedom})}$$

Q: Which formula is used to calculate the covariance between two variables $$X$$ and $$Y$$?

$$\text{Cov}(X, Y) = \frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})(y_i - \bar{y})$$

Question 1

Which formula is used to calculate the expected count for a cell in a contingency table when performing a Chi-Square Test for Independence?

Accepted Answer

$$\frac{	ext{Row Total} 	imes 	ext{Column Total}}{	ext{Grand Total}}$$

Question 2

A call center receives 700 calls per week. To test if calls are equally distributed across all days, what is the expected number of calls per day under the null hypothesis?

Accepted Answer

$$100$$

Question 3

What is the formula for the Chi-Square Test Statistic in a test of independence or goodness of fit?

Accepted Answer

$$\$$chi^2$$ = \sum \frac{(O_i - E_i)^2$}{E_i}$$

Question 4

How do you calculate the degrees of freedom for a Chi-Square Test for Independence in a contingency table with $$r$$ rows and $$c$$ columns?

Accepted Answer

$$(r-1) 	imes (c-1)$$

Question 5

Which Excel function is used to calculate the p-value for a Chi-Square Test Statistic?

Accepted Answer

$$	ext{CHISQ.DIST.RT(	ext{test statistic}, 	ext{degrees of freedom})}$$

Question 6

If the calculated p-value for a Chi-Square Test of Goodness of Fit is less than 0.05, what is the correct conclusion?

Accepted Answer

Reject the null hypothesis; the observed distribution differs significantly from the expected distribution.

Question 7

Which statement about correlation is TRUE?

Accepted Answer

Correlation measures the strength and direction of a linear relationship between two quantitative variables.

Question 8

Given a correlation coefficient $$r = -0.85$$, which of the following best describes the relationship between the two variables?

Accepted Answer

Strong negative linear relationship

Question 9

Which formula is used to calculate the covariance between two variables $$X$$ and $$Y$$?

Accepted Answer

$$	ext{Cov}(X, Y) = \frac{1}{n-1} \sum_{i=1}^{n} (x_i - \bar{x})(y_i - \bar{y})$$

Question 10

In a simple linear regression, which variable is placed on the horizontal axis of a scatterplot?

Accepted Answer

Explanatory variable ($$X)$$

Question 11

What does the slope in a simple linear regression equation represent?

Accepted Answer

The expected change in $$Y$$ for a one-unit increase in $$X$$

Question 12

Which formula gives the $$R^2$$ value in a simple linear regression?

Accepted Answer

$$R^2$$ = $$r^2$$

Question 13

Which of the following is a condition for using simple linear regression?

Accepted Answer

The relationship between $$X$$ and $$Y is $$linear.

Question 14

If the residuals from a regression model show a clear pattern over time, what does this indicate?

Accepted Answer

The model may violate the independence assumption.

Question 15

What is the effect of an outlier on a simple linear regression model?

Accepted Answer

It can significantly affect the slope and intercept estimates.

Question 16

Which statistic is used to test for autocorrelation in the residuals of a regression model?

Accepted Answer

Durbin-Watson Statistic

Question 17

A business analyst wants to predict next month's sales using a regression model. Which interval should they use to estimate the range for a single future value?

Accepted Answer

Prediction interval

Question 18

Which of the following statements about $$R^2 in $$regression is correct?

Accepted Answer

$$R^2$$ represents the fraction of the variation in $$Y$$ accounted for by the regression model.

Question 19

Which of the following is NOT a correct interpretation of a correlation coefficient $$r = 0$$?

Accepted Answer

There is no linear relationship between the two variables.

Statistics for Business: Exam 2 Review Study Notes

Guida di studio - Domande di pratica

Study guide - Flashcard