Question

HW 25 #7

Cora wants to determine a 80 percent confidence interval for the true proportion of high school students in the area who attend their home basketball games. How large of a sample must she have to get a margin of error less than 0.02? Assume we have no prior estimate of the proportion and want a conservative choice for the sample size.

[Round to the smallest integer that works.] n =

Answer #1

Solution,

Given that,

= 0.5

1 - = 0.5

margin of error = E =0.02

At 80% confidence level

= 1 - 80%

= 1 - 0.80 = 0.2

/2
= 0.1

Z/2
= Z0.1 = 1.282

sample size = n = (Z / 2 / E )2 * * (1 - )

= ( 1.282 / 0.02 )2 * 0.5 * 0.5

= 1027

**sample size = n = 1027**

Dylan wants to determine a 95 percent confidence interval for
the true proportion of high school students in the area who attend
their home basketball games. How large of a sample must he have to
get a margin of error less than 0.02? [To find n, use the value p*
= 1/2 for the sample proportion and the values for z* from a
z-table or t-table.]
[Round to the smallest integer that works.] n =

(1 point) Dylan wants to determine a 99 percent confidence
interval for the true proportion of high school students in the
area who attend their home basketball games. How large of a sample
must he have to get a margin of error less than 0.02? [To find n,
use the value p* = 1/2 for the sample proportion and the values for
z* from a z-table or t-table.] [Round to the smallest integer that
works.] n =

1) Kim wants to determine a 99 percent confidence interval for
the true proportion p of high school students in the area who
attend their home basketball games. Out of n randomly selected
students she finds that that exactly half attend their home
basketball games. About how large would ? have to be to get a
margin of error less than 0.01 for p?
[Use the values for z* from a z-table or t-table, and round to the
smallest integer...

Kim wants to determine a 90 percent confidence interval for the
true proportion of high school students in the area who attend
their home basketball games. How large of a sample must she have to
get a margin of error less than 0.03?
HINT: To find n, since no previous study has been done, use the
value p = 0.5 for the proportion and one of the values (1.282,
1.645, 1.96, 2.576) for the critical value depending on the
confidence...

Kim wants to determine a 80 percent confidence interval for the
true mean serumHDL cholesterol 20-29 year old females. How large of
a sample must she have to get a margin of error less than 2 points?
Assume the population standard deviation is 13.4 points.

A researcher wants to construct a 95% confidence interval for
the proportion of elementary school students in Seward County who
receive free or reduced-price school lunches. What sample size is
needed so that the confidence interval will have a margin of error
of 0.03?

How's the economy? A pollster wants to construct a 95 %
confidence interval for the proportion of adults who believe that
economic conditions are getting better.
(a) A poll taken in July 2010 estimates this proportion to be
0.41 . Using this estimate, what sample size is needed so that the
confidence interval will have a margin of error of 0.02 ?
(b) Estimate the sample size needed if no estimate of p is
available. Part 1 of 2
(a)...

Reading proficiency: An educator wants to construct a 98%
confidence interval for the proportion of elementary school
children in Colorado who are proficient in reading.
(a) The results of a recent statewide test suggested that the
proportion is 0.61 Using this estimate, what sample size is needed
so that the confidence interval will have a margin of error of
0.03?

A sociologist wants to construct a 95% confidence interval for
the proportion of children aged 8–12 living in New York who own a
cell phone. A survey estimated the nationwide proportion to be
0.56. What sample size is needed so that the confidence interval
will have a margin of error of 0.02? (Provide your answer as a
whole number).

A
pollster wants to construct a 95% confidence interval for the
proportion of adults who believe that economic conditions are
getting better. A Gallup poll taken in July 2010 estimates this
proportion to be 0.33. Using this estimate, what sample size is
needed so that the confidence interval will have a margin of error
of 0.034 ?
Write only an integer as your answer .

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 5 minutes ago

asked 16 minutes ago

asked 16 minutes ago

asked 19 minutes ago

asked 23 minutes ago

asked 24 minutes ago

asked 30 minutes ago

asked 40 minutes ago

asked 40 minutes ago

asked 45 minutes ago

asked 1 hour ago

asked 1 hour ago