10 MCQs in Statistics ...

1. When the level of confidence and sample proportion remain the same, a confidence interval for a population proportion p based on a sample of n = 100 will be _____ a confidence interval for p based on a sample of n = 400.
a. wider than
b. narrower than
c. equal to
 

2. If the population proportion is .4 with a sample size of 20, then is this sample large enough so that the sampling distribution of is a normal distribution.
True
False
 

3. When the population is normally distributed, population standard deviation ó is unknown and the sample size is n = 15, the confidence interval for the population mean µ is based on
a. the z (normal) distribution.
b. the t distribution.
c. the Binomial distribution.
d. the Poisson Distribution.
e. None of the above.
 

4. When the sample size and the sample proportion remain the same, a 90% confidence interval for a population proportion p will be ______ the 99% confidence interval for p.
a. wider than
b. narrower than
c. equal to
 

5. For non-normal populations, as the sample size (n) _________, the distribution of sample means approaches a/an __________ distribution.
a. decreases, uniform
b. increases, normal
c. decreases, normal
d. increases, uniform
e. increases, exponential
 

6. Whenever the sampled population has a normal distribution, the sampling distribution of is a normal distribution for
a. only large sample sizes.
b. only small sample sizes.
c. any sample size.
d. only samples of size 30 or more.
 

7. Assuming the same value of a, as the sample size increases, the value of ta/2 approaches the value of Za/2. (Points : 1)
True
False
 

8. As our sample standard deviation increases when all other parts of the confidence interval stay the same, then the confidence interval will become:
a. wider
b. narrower
c. remain the same.
 

9. A manufacturing company measures the weight of boxes before shipping them to the customers. If the box weights have a population mean and standard deviation of 90 lbs and 24 lbs respectively, then, based on a sample size of 36 boxes, the probability that the average weight of the boxes will be less than 84 lbs is
a. 16.87%.
b. 93.32%.
c. 43.32%.
d. 6.68%.
e. 84.13%.
 

10. If the sampled population has mean 48 and standard deviation 16, then the mean and the standard deviation for the sampling distribution of for n = 16 are
a. 4 and 1.
b. 12 and 4.
c. 48 and 4.
d. 48 and 1.
e. 48 and 16.