Question

please answer all the questions

1. A Confidence Interval (CI) for a population characteristic is:

- An alternative to a Point Estimate
- An interval of plausible values for a population characteristic
- An interval of ranges for a large sample that is unbiased
- A population of critical values

Directions: Find each specified point estimate or confidence interval.

2. A survey of teachers reports that a point estimate for the mean amount of money spent each week on lunch is $18.00. If the margin of error for a 95% confidence interval for the mean amount of money spent each week on lunch by all teachers is $1.70, construct a 95% confidence interval for the mean amount of money spent each week on lunch for all teachers.

- 16.30<
*μ*<19.70 - 18.00<μ<19.70
- 16.30<
*μ*<16.30 - 18.30<
*μ*<19.70

Directions: Calculate the margin of error (E) of a confidence interval for the population mean at the given level of confidence.

3. n = 134, σ = 0.27, c = 0.99

- 0.06
- 0.90
- 0.99
- 0.27

Directions: Construct a confidence interval for the population mean at the given level of confidence.

4. n = 64, σ = 8.01, c = 0.90, x = 90.40

- 90.75<μ<92.05
- 64.00<μ<90.40
- 88.75<μ<92.05
- 64.75<μ<92.05

Directions: Calculate the minimum sample size needed to construct a confidence interval with the desired characteristics.

5. E = 2, σ = 12.10, c = 0.90

- Need a minimum sample size of 90
- Need a minimum sample size of 30
- Need a minimum sample size of 10
- Need a minimum sample size of 100

Answer #1

1. A Confidence Interval (CI) for a population characteristic is:

**An interval of plausible values for a population characteristic**

Use the confidence interval, (36.482, 41.352), to answer the
questions.
What is the margin of error, E?
What is the sample mean, x?
Let c = 0.99, σ = 3.7, and E = 2.2. What is the minimum sample
size, n, needed to estimate μ

For the following questions construct the indicated confidence
interval for the population mean. Note c = confidence level, x ̅
which is equal to the sample mean, s = standard deviation, and n =
sample size
a. c = 0.90, x ̅ = 12.3, s = 1.5, n = 50
b. c = 0.99, x ̅ = 10.5, s = 2.14, n = 45

Construct a 90% confidence interval to estimate the population
mean using the accompanying data. What assumptions need to be made
to construct this interval?
x= 55 σ= 11 n=16
What assumptions need to be made to construct this
interval?
A. The sample size is less than 30.
B. The population must be normally distributed.
C. The population is skewed to one side.
D. The population mean will be in the confidence interval.

Construct the confidence interval for the population mean
μ.
c=0.90, x=16.1, σ=8.0, and n=85
A 90% confidence interval for
μ is ( , ).
(Round to one decimal place as needed.)

Construct the confidence interval for the population mean mu μ.
c equals = 0.90 0.90, x overbar equals 15.8 x=15.8, sigma σ
equals = 6.0 6.0, and n equals = 70 70 A 90 90% confidence
interval for mu μ is left parenthesis nothing comma nothing right
parenthesis . , . (Round to one decimal place as needed.).

Suppose you are calculating the minimum sample size required for
a confidence interval about a population mean and you know σ. Which
of the following does not influence the minimum sample size?
A. the size of the population
B. confidence level
C. the acceptable margin of error
D. the size of the population standard deviation (σ)

Assume the sample is taken from a normally distributed
population and construct the indicated confidence
interval.
Construct the indicated confidence intervals for the population
variance σ 2 and the population
standard deviation σ. Assume the sample is from a normally
distributed population
c = 0.99, s = 228.1 , n
= 61

Question 1
A researcher wishes to find a 90% confidence interval estimate
for an unknown population mean using a sample of size 25. The
population standard deviation is 7.2.
The confidence factor z α 2for this est
Group of answer choices
1.28
1.645
1.96
Question 2
A 90% confidence interval estimate for an unknown population
mean μ is (25.81, 29.51).
The length of this CI estimate is
Group of answer choices
1.96
1.85
3.7
1.645
Question 3
Data below refers...

Construct the indicated confidence interval for the population
mean μ using the t-distribution. Assume the population is normally
distributed.
ce=0.99, x =13.9, s=3.0, n=6
The 99% confidence interval using a t-distribution is
____________.(Round to one decimal place as needed.)

1,) Construct a 90% confidence interval for the population
proportion if an obtained sample of size n = 150 has x = 30
2.) Construct a 95% confidence interval for the population mean
if an obtained sample of size n = 35 has a sample mean of 18.4 with
a sample standard deviation of 4.5.

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