Question

Use Excel please.( norm.inv, t.inv, )

QUESTION 2

(a) Suppose that your task is to estimate the mean of a normally
distributed population to within 8 units with 95% confidence and
that the population standard deviation is known to be 72. What
sample size should be used if you wish to estimate the population
mean to within 8 units?

(b) Determine the minimum sample size required for estimating the
population proportion of number of people who drive to work, to
within 0.002, with 90% confidence.

(c) As a manufacturer of golf clubs, a major corporation wants to
estimate the proportion of golfers who are right-handed. How many
golfers must be surveyed if they want to be within 0.03 with a 99%
confidence level:

i. assuming that there is no information available that could be
used as an estimate of p?

ii. assuming that the manufacturer has an estimate of p obtained
from a previous study that suggests that 75% of golfers are
right-handed?

(d) The population proportion of voters in favour of a particular
political

Answer #1

(a) A senatorial candidate wants to estimate the proportion of
people in his voting district who will favour a balanced-budget
amendment, which is debatable. He wants this estimate to be within
0.03 of the population proportion for a 98%98% confidence interval.
What is the sample size needed to produce this level of
accuracy?
(b) A researcher wants to make a 95%95% confidence interval for
the population mean. The population standard deviation is
25.5025.50. What sample size is required so that...

(S 9.1) Determine the minimum sample size required in order to
estimate p, the population proportion, to within 0.03,
with:
a) 95% confidence.
b) 99% confidence.

In order to estimate the population proportion of Texas voters
who support a state sales tax for public schools to within 5% with
95% confidence, the sample size should be:
A. 271
B. 384
C. 385
D. None of the above

1. A sample of 35 circuits from a large normal population has
a mean resistance of 2.35 ohms. We know from past testing that
the
a) population standard deviation is 0.45 ohms. b) population
standard deviation is 0.48 ohms. c) population standard deviation
is 0.43 ohms. d) population standard deviation is 0.46 ohms.
Determine a 95% confidence interval for the true mean
resistance of the population
2. a)Arandomsampleofn=20has x=45ands=8.
b)Arandomsampleofn=22has x=48ands=9.
c)Arandomsampleofn=20has x=45ands=8.
d)Arandomsampleofn=22has x=48ands=9. Form a 95% confidence
interval...

Suppose you want to estimate the percentage of people who smoke,
and you want your estimate to be within 3 percentage points of the
correct population measure, based upon an 90% confidence level.
What minimum size sample is required? Assume that no estimate of
"p-hat" is known.

A researcher wishes to estimate, with 99% confidence, the
population proportion of adults who think the president of their
country can control the price of gasoline. Her estimate must be
accurate within 5% of the true proportion.
a) What is the minimum sample size needed assuming that no prior
information is available? (round to nearest whole #)
b) What is the minimum sample size needed using a prior study
that found that 32% of the respondents said they think their...

A survey of 250 voters was conducted to determine who they would
vote for in an upcoming election for sheriff. Fifty-five percent
said they would vote for Longmire.
A/ What is the best unbiased estimate of the population
proportion that will vote for Longmire (in other words, what is
?)
B/ Find the margin of error E that corresponds to a 90% confidence
Interval.
C/ Construct the 90% confidence interval about the population
proportion p.
D/ Based on your results,...

Q6 a) A population standard
deviation is estimated to be 15. We want to estimate the population
mean within 1.2, with a 95-percent level of confidence. What sample
size is required?
b) Orla is the new statistician at a cola company.
She wants to estimate the proportion of the population who enjoy
their latest idea for a flavour enough to make it a successful
product. Orla wants to obtain a 95-percent confidence level
estimate of the population proportion and she wants...

4) To estimate the population proportion of a given survey, what
sample size would be required if we want a margin of error of
0.045; a confidence level of 95%; and p and q are unknown.
5). How many cars must be randomly selected and tested in order
to estimate the mean braking distance of registered cars in the US?
We want a 99% confidence that the sample mean is within 2 ft of the
population mean, and the population...

The sample size needed to estimate a population mean to within
50 units was found to be 97. If the population standard deviation
was 250, then the confidence level used was:
a) 90%
b) 95%
c) 98%
d) 99%
e) None of the above.

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