Question

** 8.** A random sample is obtained from a
normal population with a mean of µ = 80 and a standard deviation of
σ = 8. Which of the following outcomes is more likely? Explain your
answer.

A. A sample mean greater than 86 for a sample of n = 4 scores.

B. A sample mean greater than 84 for a sample of n = 16 scores.

** 9.** The distribution of SAT scores is
normal with a mean of µ = 500 and a standard deviation of σ = 100.
If the mean SAT score is computed from a sample of n = 100 students
from this population…

A. What range of values should contain the sample mean 95% of the time?

B. What range of values should contain the sample mean 99% of the time?

Answer #1

A sample of n = 4 scores is selected from a normal
population with a mean of µ = 50 and a standard deviation
of σ = 20. What is the probability of obtaining a sample
mean greater than M = 48?

A normal population has a mean of µ = 100. A sample of n = 36
is selected from the population, and a treatment is administered to
the sample. After treatment, the sample mean is computed to be
M = 106. Assuming that the population standard deviation
is σ = 12, use the data to test whether or not the treatment has a
significant effect. Use a one tailed test.
Hypothesis:
Zcrit =
z test
calculation:
Conclusion:

A random
sample is selected from a normal population with a mean of µ = 30
and a standard deviation of σ= 8. After a treatment is administered
to the individuals in the sample, the sample mean is found to be x̅
=33.
Furthermore,
if the sample consists of n = 64 scores, is the sample
mean sufficient to conclude that the treatment has a significant
effect? Use a two-tailed test with α = .05.
4a. Which of
the following...

A sample data is drawn from a normal population with unknown
mean µ and known standard deviation σ = 5. We run the test µ = 125
vs µ < 125 on a sample of size n = 100 with x = 120. Will you be
able to reject H0 at the signiﬁcance level of 5%?
A. Yes
B. No
C. Undecidable, not enough information
D. None of the above

A random sample of size 36 is taken from a population with mean
µ = 17 and standard deviation σ = 4. The probability that the
sample mean is greater than 18 is ________.
a. 0.8413
b. 0.0668
c. 0.1587
d. 0.9332

A researcher selects a sample of n = 100 from a normal
population with µ = 50 and σ = 30. If the
treatment is expected to decrease scores by 10 points, what is the
power of a two-tailed hypothesis test using α = .05?

IQ scores are standardized to produce a normal distribution with
a mean of µ = 100 and a standard deviation of σ = 15. Find the
proportion of the population in the following IQ category: IQ
greater than 160. The proportion is Group of answer choices .0039
.49997 .008 .00003

A random sample of size 49 is taken from a population with mean
µ = 26 and standard deviation σ = 7. Use an appropriate normal
transformation to calculate the probability that the sample mean is
between 24 and 27.
Group of answer choices
0.0228
0.8641
0.8413
0.8185

A random sample of size 64 is taken from a population with mean
µ = 17 and standard deviation σ = 16. What are the expected value
and the standard deviation for the sampling distribution of the
sample mean?

The sample mean and standard deviation from a random sample of
33 observations from a normal population were computed as x¯=34 and
s = 8. Calculate the t statistic of the test required to determine
whether there is enough evidence to infer at the 10% significance
level that the population mean is greater than 30.

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