Statistics

Which of the following might have resulted from poor sampling design for
a survey that attempts to determine the political opinions of the
residents of a state?

The respondents misrepresent their level of income

The sample fails to include a representative portion of minorities

In a random sample, 90% indicate that they’re Republicans

In a simple random sample of 1000 automobile owners between the ages of
25 and 35, there were 142 owners of Ford Explorers. If the expected
number of owners of this vehicle was 125 out of 1000, what are the p and
n respectively?

A marketing consultant is engaged in a project to estimate the
proportion of homes receiving both HBO and Showtime cable service. The
consultant plans to use a confidence coefficient of 0.95 and a maximum
error of the estimate equal to 0.10. If 2500 homes in this city receive
cable service, determine the sample size for the consultant to use.

The Coca-Cola Company has 40$ of the cola market. Determine the
probability that a sample proportion for n=30 is within 0.10 of the true
population proportion of 0.40, which represents the proportion of cola
drinkers who prefer a Coca-Cola drink.

Determine which of the following four population size and sample size
combinations would not require the use of the finite population
correction factor in calculating the standard error.

N=150; n=25

N=1500; n=300

N=2500; n=75

N=15000; n=1000

A federal auditor for nationally chartered banks, from a random sample
of 100 accounts, found that the average demand deposit balance at the
First National Bank of Arkansas was $549.82. If the auditor needed a
point estimate for the population mean for all accounts at this bank,
what should he use?

a. The average of $54.98 for this sample

b. The average of $539.82 for this sample.

c. There’s no acceptable value available

d. The auditor should survey the total of all accounts and determine the
mean

In order to schedule appointments better, the office manager for an
ophthalmologist wants to estimate the average time that the doctor
spends with each patient. A random sample of 49 is taken, and the
sample mean is 20.3 minutes. Assume that the office manager knows from
past experience that the standard deviation is 14 minutes. She finds
that a 95% confidence interval is between 18.3 and 22.3 minutes. What
is the point estimate of the population mean, and what is the confidence
coefficient?

A mortgage broker is offering home mortgages at a rate of 9.5%, but the
broker is fearful that this value is higher than many others are
charging. A sample of 40 mortgages filed in the county courthouse shows
an average of 9.25% with a a standard deviation of 8.61%. Does this
sample indicate a smaller average? Use a=0.05 and assume a normally
distributed population.