MATH235 Week 2  - Moodle Quiz-assessed problems

Confidence interval 1
The 90% confidence interval for $\mu$ is

1. (a)

   (80.6,120.6)

2. (b)

   (90.8,110.5)

3. (c)

   (83.3,118.0)

4. (d)

   (97.6,103.7)

5. (e)

   (98.0,105.5)

[marks: 2]

Hypothesis test
Using your confidence interval, is there evidence that the mean CPI for France exceeds 94? At what significance level do you draw your conclusion?

1. (a)

   Yes, at the 5% level

2. (b)

   Yes, at the 10% level

3. (c)

   No, at the 2.5% level

4. (d)

   No, at the 5% level

5. (e)

   No, at the 10% level

[marks: 2]

The remaining quiz questions use the data in Table 0.7 to test whether or the mean height of males in the Childhood Respiratory Disease Study is greater than that of females. Assume that the data are unpaired and that they are each IID samples from Normal$({\mu }_i,{\sigma }^2)$ distributions; where ${\mu }_1$ is the mean male height and ${\mu }_2$ is the mean female height.

Pooled sample variance
What is the value of the pooled sample standard deviation for these data?

1. (a)

   5.08

2. (b)

   5.22

3. (c)

   27.20

4. (d)

   25.80

5. (e)

   4.95

[marks: 2]

Difference in means
Which of the following is a 95% confidence interval for the difference in means ${\mu }_1-{\mu }_2$?

1. (a)

   (-4.79,5.49)

2. (b)

   (-24.64,25.35)

3. (c)

   (4.44,5.14)

4. (d)

   (-10.61,11.31)

5. (e)

   (-26.44,27.14)

[marks: 2]

Conclusion
From your confidence interval, which of the following is true?

1. (a)

   There is evidence of a difference in mean heights between genders at the 10% level

2. (b)

   There is evidence of a difference in mean heights between genders at the 5% level

3. (c)

   There is evidence of a difference in mean heights between genders at the 2.5% level

4. (d)

   There is no evidence of a difference in mean heights between genders at the 5% level

5. (e)

   There is no evidence of a difference in mean heights between genders at the 2.5% level

[marks: 2]