COHP 350 Final Exam Review Questions And Answers
What was the purpose of William Goset creating the "student" t-distribution, which is the main difference from the z-normal distribution? ANS t-distribution was used for smaller sample sizes
A 95 percent confidence interval is that range of valu...
what was the purpose of william goset creating the
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COHP 350 Final Exam Review Questions And
Answers
What was the purpose of William Goset creating the "student" t-distribution, which is the main difference from the
z-normal distribution? ANS t-distribution was used for smaller sample sizes
A 95 percent confidence interval is that range of values around a sample mean that has a 0.95 probability of
containing the true population mean. ANS True
The U.S. Census Bureau conducts a study to determine the time needed to complete the short form. The Bureau
surveys 200 people. The sample mean is 8.2 minutes. There is a known standard deviation of 2.2 minutes. The
population distribution is assumed to be normal.
Identify the following:
a. = _____ [a]
b. σ = _____ [b]
c. n = _____ [c] ANS a. 8.2
b. 2.2
c. 200
A hospital is trying to cut down on emergency room wait times. It is interested in the amount of time patients must
wait before being called back to be examined. An investigation committee randomly surveyed 70 patients. The
sample mean was 1.5 hours with a sample standard deviation of 0.5 hours. Identify the following:
a. = ____ [a]
b. sx = ____ [b]
c. n = ____ [c]
d. n - 1 = ____ [d]
A 95% confidence interval (CI) was constructed with the following results:
CI: (1.3808, 1.6192)
Explain what the confidence interval means in this problem by filling in the missing information:
We are 95% confident that the ________ [e] waiting time is between ________ [f] and ________ [g] for patients in
the emergency room before being called back to be examined. ANS a. sample mean = 1.5
b. sample standard deviation = 0.5
c. sample size = 70
d. degrees of freedom = n-1 = 70-1 =69
, e. population mean
f. 1.38 hours
g. 1.62 hours
Suppose the marketing company did do a survey. They randomly surveyed 200 households and found that in 120 of
them, the woman made the majority of the purchasing decisions. We are interested in the population proportion of
households where women make the majority of the purchasing decisions. Identify the following:
a. x = ______ [a]
b. n = ______ [b]
c. p = ______ [c] ANS a. 120
b. 200
c. 0.6
You are conducting medical research and need to be 95% confident that an interval between 9.55 and 21.3 captures
the true mean of the research. You do not, however, know the population standard deviation. Which type of
distribution should you use for this problem? [a] Why would you use your distribution choice? [b] ANS a.
Students t-distribution
b. We don't know the population standard deviation
The bell curve below signifies cholesterol levels of a small sample (<30) of patients at a rural medical facility.
Which of the following statements pertain to this descriptive statistic? ANS all of the above statements describe
the curve display
A biologist has taken a random sample of a specific type of fish from a large lake to check for levels of mercury. A
95 percent confidence interval was calculated to be 6.8 ± 1.2 pounds. Re-read the definition of a confidence interval
then choose which of the following is true. ANS In repeated sampling, 95 percent of the time the true population
mean of the weight of the fish will be included in this confidence interval
A quality control specialist at a medical supply factory must estimate the mean quality rating of a new batch of
surgical tools being produced using a sample of 18 tools. The actual distribution of this batch is unknown, but
preliminary investigations show that a normal approximation is reasonable. The specialist decides to use a t-
distribution rather than a z-distribution because? ANS The variability of the batch is unknown
The mean entry level salary of a full-time respiratory therapist at a local hospital is $42,000 per year. It is believed to
be higher for nurses in the same hospital. State the null and alternative hypotheses (two answers required - you must
write out the entire statements for credit). ANS Ho: μ = 42,000
Ha: μ > 42,000
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