BSTAT EXAM REVISION
QUESTIONS AND 100% CORRECT
ANSWERS!!
A 99% confidence interval for the population mean yields the following results: [−3.79,
5.86]. At the 1% significance level, what decision should be made regarding the
following hypothesis test with Ho:μ = 0,HA:μ ≠ 0?
Do not reject Ho; we cannot conclude that the mean differs from zero.
A 99% confidence interval estimate can be interpreted to mean that
if all possible samples of the same size are taken and confidence interval estimates are
developed, 99% of them would include the true population mean somewhere within their
interval.
Find the z value such that P(Z ≤ z) = 0.9082.
z = 1.33
A fast-food franchise is considering building a restaurant at a busy intersection. A financial
advisor determines that the site is acceptable only if, on average, more than 300
automobiles pass the location per hour. The advisor tests the following hypotheses:Ho: μ ≤
300.HA: μ > 300.The consequences of committing a Type II error would be that
the franchiser does not build on an acceptable site
A random sample of size 100 is taken from a population described by the proportion p =
0.60.The probability that the sample proportion is less than 0.55 is ______.
0.1537
For a given confidence level 100(1-a)% and sample size n, the width of the confidence
interval for the population mean is narrower, the greater the population standard
deviation σ.
False
, Candidate A is facing two opposing candidates in a mayoral election. In a recent poll of
300 residents, 144 supported A. Construct a 99% confidence interval on the population
proportion for the support of candidate A in the following election.
[0.4057, 0.5543]
What is the minimum sample size required to estimate a population mean with 95%
confidence when the desired margin of error or bound on error is B = 1.5? The
population standard deviation is known to be 10.75.
n = 198
What is ta/2, df for a 95% confidence interval of the population mean based on a sample
of 25 observations?
2.064
Like the z distribution, the tdf distribution is symmetric around 0, bell-shaped, and with
tails that approach the horizontal axis and eventually cross it.
False
If X has a normal distribution with µ = 100 and σ = 5, then the probability P(90 ≤ X ≤ 95)
can be expressed in terms of a standard normal variable Z as
P(-2 ≤ Z ≤ -1)
Consider the following hypotheses:H0: p ≥ 0.38HA: p < 0.38Compute the p-value based on
the following sample information. x = 110; n = 300
.3192
A basketball coach wants to know how many free throws an NBA player shoots during the
course of an average practice. The coach takes a random sample of 43 players and finds the
average number of free throws shot per practice was 225 with a standard deviation of 35.
Construct a 99% confidence interval for the average number of free throws in practice.
[210.5992, 239.4008]
The central limit theorem approximation improves as the sample size decreases.
False
QUESTIONS AND 100% CORRECT
ANSWERS!!
A 99% confidence interval for the population mean yields the following results: [−3.79,
5.86]. At the 1% significance level, what decision should be made regarding the
following hypothesis test with Ho:μ = 0,HA:μ ≠ 0?
Do not reject Ho; we cannot conclude that the mean differs from zero.
A 99% confidence interval estimate can be interpreted to mean that
if all possible samples of the same size are taken and confidence interval estimates are
developed, 99% of them would include the true population mean somewhere within their
interval.
Find the z value such that P(Z ≤ z) = 0.9082.
z = 1.33
A fast-food franchise is considering building a restaurant at a busy intersection. A financial
advisor determines that the site is acceptable only if, on average, more than 300
automobiles pass the location per hour. The advisor tests the following hypotheses:Ho: μ ≤
300.HA: μ > 300.The consequences of committing a Type II error would be that
the franchiser does not build on an acceptable site
A random sample of size 100 is taken from a population described by the proportion p =
0.60.The probability that the sample proportion is less than 0.55 is ______.
0.1537
For a given confidence level 100(1-a)% and sample size n, the width of the confidence
interval for the population mean is narrower, the greater the population standard
deviation σ.
False
, Candidate A is facing two opposing candidates in a mayoral election. In a recent poll of
300 residents, 144 supported A. Construct a 99% confidence interval on the population
proportion for the support of candidate A in the following election.
[0.4057, 0.5543]
What is the minimum sample size required to estimate a population mean with 95%
confidence when the desired margin of error or bound on error is B = 1.5? The
population standard deviation is known to be 10.75.
n = 198
What is ta/2, df for a 95% confidence interval of the population mean based on a sample
of 25 observations?
2.064
Like the z distribution, the tdf distribution is symmetric around 0, bell-shaped, and with
tails that approach the horizontal axis and eventually cross it.
False
If X has a normal distribution with µ = 100 and σ = 5, then the probability P(90 ≤ X ≤ 95)
can be expressed in terms of a standard normal variable Z as
P(-2 ≤ Z ≤ -1)
Consider the following hypotheses:H0: p ≥ 0.38HA: p < 0.38Compute the p-value based on
the following sample information. x = 110; n = 300
.3192
A basketball coach wants to know how many free throws an NBA player shoots during the
course of an average practice. The coach takes a random sample of 43 players and finds the
average number of free throws shot per practice was 225 with a standard deviation of 35.
Construct a 99% confidence interval for the average number of free throws in practice.
[210.5992, 239.4008]
The central limit theorem approximation improves as the sample size decreases.
False
