Question 1

Which of the following is the correct null hypothesis ($$H_0) $$for a one-way ANOVA test comparing the means of $$k$$ groups?

Accepted Answer

$$H_0$$: \$$mu_1$$ = \$$mu_2$$ = \ldots = \mu_k$$

Question 2

In the context of ANOVA, what does the F-statistic represent?

Accepted Answer

The ratio of the variance between group means to the variance within the groups

Question 3

Given the following ANOVA table summary for three groups (A, B, C):

Source | df | SS | MS | F | p-Value
Between | 2 | 2984.332 | 1492.166 | 4.871 | 0.028
Within | 12 | 3565.133 | 297.094 |   |   
Total | 14 | 6549.466 |   |   |

At a significance level of $$\alpha = 0.02$$, what is the correct conclusion?

Accepted Answer

Fail to reject $$H_0$$; there is not enough evidence that the means are different.

Question 4

Which of the following is NOT an assumption required for conducting a one-way ANOVA?

Accepted Answer

The response variable is categorical.

Question 5

Suppose a researcher conducts an ANOVA test and obtains a p-value of 0.129 at a significance level of $$\alpha = 0.02. $$What should the researcher conclude?

Accepted Answer

Fail to reject the null hypothesis; there is not enough evidence that the means are different.

Question 6

Given the formulas for ANOVA:

$$SSB = SST - SSW$$
$$MSB = \dfrac{SSB}{k-1}$$
$$MSW = \dfrac{SSW}{N-k}$$
$$F = \dfrac{MSB}{MSW}

If$$ $$SSB = 54.15$$, $$SSW = 76.00$$, $$k = 4$$, and $$N = 20$$, what is the value of $$F$$?

Accepted Answer

$$F = \dfrac{18.05}{4.75} = 3.80$$

Question 7

A company wants to compare the mean number of annual accidents at four different plants. The ANOVA test yields a p-value of 0.0307. At a 5% significance level, what is the correct interpretation?

Accepted Answer

Reject the null hypothesis; there is evidence that at least one plant's mean is different.

Question 8

Which formula correctly calculates the degrees of freedom for the 'within' group in a one-way ANOVA with $$N$$ total observations and $$k$$ groups?

Accepted Answer

$$df_W = N - k$$

Question 9

In an ANOVA test, if the calculated F-statistic is much larger than 1, what does this suggest about the group means?

Accepted Answer

There is likely a significant difference among the group means.

Question 10

A researcher is comparing the mean sound levels (dBA) of three engine types using ANOVA. The p-value is 0.129. At a 15% significance level, what should the researcher conclude?

Accepted Answer

Reject the null hypothesis; there is evidence that at least one mean is different.

Question 11

Which of the following best describes the purpose of the ANOVA F-test in the context of comparing means?

Accepted Answer

To determine if at least one group mean is significantly different from the others

Question 12

If the ANOVA test results in a p-value less than the chosen significance level $$\alpha$$, what is the correct statistical decision?

Accepted Answer

Reject the null hypothesis

Question 13

A researcher collects AQI readings from three plants and calculates the following:

$$SST = 6549.466$$, $$SSW = 3565.133$$, $$k = 3$$, $$N = 15.

$$What is the sum of squares between groups ($$SSB$$)?

Accepted Answer

$$SSB = SST - SSW = 6549.466 - 3565.133 = 2984.333$$

Question 14

Which of the following is the correct formula for the mean square within groups ($$MSW) in $$ANOVA?

Accepted Answer

$$MSW = \dfrac{SSW}{N-k}$$

Question 15

In a real-world scenario, a hospital administrator wants to compare the average patient wait times across four departments. Which statistical test is most appropriate?

Accepted Answer

One-way ANOVA

Question 16

If the ANOVA test assumptions are violated (e.g., non-normality or unequal variances), which of the following is a potential consequence?

Accepted Answer

The Type I error rate may not be controlled, leading to invalid conclusions.

Question 17

A researcher is analyzing the effect of three fertilizers on crop yield. The ANOVA test yields $$F = 2.466$$ with $$df_B = 2$$ and $$df_W = 9. $$Which function would you use to find the p-value?

Accepted Answer

$$Fcdf(2.466, 1000, 2, 9)$$

Question 18

Which of the following best describes the meaning of a p-value in the context of ANOVA?

Accepted Answer

The probability of observing an F-statistic as extreme as, or more extreme than, the one calculated, assuming the null hypothesis is true.

Chapter 11-B

Guida di studio - Domande di pratica

Study guide - Flashcard