Question

Three separate random samples of students (one sample selected from each of three different colleges) were selected in order to estimate the population percentage of students at each college who are sophomores. Sample 1: 130 students were selected from among all those attending college number 1 and 30 of them were found to be sophomores. Sample 2: 50 students were selected from among all those attending college number 2 and 10 of them were found to be sophomores. Sample 3: The sample from college number 3 showed that 30% of students were sophomores with a margin of error of (plus or minus) 10%. (NOTE: You should only enter numbers in the blanks provided. For example, to enter "20%" you would type "20" in the blank.) (a) If sample 1 is used to estimate the population percentage of students at college number 1 who are sophomores, what is the margin of error? Enter the margin of error as a percentage rounded to one decimal place: percent. (b) If sample 2 is used to estimate the population percentage of students at college number 2 who are sophomores, what is the margin of error? Enter margin of error as a percentage rounded to one decimal place: percent. (c) If sample 3 is used to estimate the population percentage of students at college number 3 who are sophomores, then an interval that "almost certainly" contains the true population percentage is: percent to percent. (Enter lower-bound in first blank and upper-bound in second blank.) Can someone help me with A and B?

Answer #1

Three separate random samples of students (one sample selected
from each of three different colleges) were selected in order to
estimate the population percentage of students at each college who
are sophomores.
Sample 1: 120 students were selected from among all those
attending college number 1 and 30 of them were found to be
sophomores.
Sample 2: 65 students were selected from among all those
attending college number 2 and 10 of them were found to be
sophomores.
Sample 3:...

Random samples of students at 122 four-year colleges were
interviewed several times since 1995. Of the students who
reporteddrinking alcohol the percentage who reported bingeing at
least three times within the past two weeks was 41.4% of 333
students in 1995 and 21% of 841 students in 2007
a. Estimate the difference between the proportions in 2007and
1995, interpret.
b. Find the standard error for this difference. Interpret
it.
c. Define the two relevant population parameters to compare in
the...

4. Find the margin of error E. In a random sample of 151 college
students, 84 had part-time jobs. Find the margin of error E for the
95% confidence interval used to estimate the population proportion.
Round your answer to four decimal places. Answer 0.0792
5. Find the minimum sample size required to estimate the
population proportion p: Margin of error: 0.10; confidence level:
95%; from a prior study, is known to be 66%.
6. Find the minimum sample size...

one sample showed that among 780 randomly selected students who
completed four years of college 20% smoke. Use a=0.02 significance
level to test the claim that the rate of smoking among those four
years of college is less than 27% rate for the general
population

Two hundred students were selected at random from those enrolled
at a large college in Alabama. Each student in the sample was asked
whether they ate 5 or more apples in a typical week, and their
cholesterol levels were also measured. The average cholesterol
level was significantly lower for the group who ate 5 or more
apples per week than for the group that did not.
A. Did the study use a random selection from some population? If
yes, what...

Independent random samples were selected from two quantitative
populations, with sample sizes, means, and standard deviations
given below. n1 = n2 = 80, x1 = 125.3, x2 = 123.6, s1 = 5.7, s2 =
6.7
Construct a 95% confidence interval for the difference in the
population means (μ1 − μ2). (Round your answers to two decimal
places.)
Find a point estimate for the difference in the population
means.
Calculate the margin of error. (Round your answer to two decimal
places.)

A sample of 152 statistics students were surveyed concerning
their future pet ownership. Of the 152 students in the sample, 82
responded that they plan on getting a dog after graduating.
Construct a 95% confidence interval for the proportion of
statistics students overall (i.e., the entirepopulation) that want
to get a dog.
Suppose we wanted to take another sample to estimate the
percent of percentage of statistics studentsthat want to get a dog.
Find the sample size we need to...

Suppose a random sample of n = 118 measurements is selected from
a population with mean μ = 26 and standard deviation σ = 3. Find
the value of the standard error rounded to one decimal place.

A random sample of 30 male college students was selected, and
their heights were measured. The heights (in inches) are given
below.
73
66
68
70
69
69
69
66
68
70
72
74
73
71
71
72
69
68
66
73
74
72
68
71
67
73
66
73
69
72
(a) Complete the frequency distribution for the data. Make sure
to enter your answers for the relative frequency as decimals,
rounded to the nearest tenth.
Height
Frequency
Relative...

5) Suppose that simple random samples of college freshman are
selected from two universities, 25 students from school A and 20
students from school B. On a standardized test, the sample from
school A has an average score of 1010 with a standard deviation of
100. The sample from school B has an average score of 990 with a
standard deviation of 90.
a) What is the 90% confidence interval for the difference in
test scores at the two schools?...

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