22 Nov 2022

139

How to Construct a Confidence Interval

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Academic level: University

Paper type: Essay (Any Type)

Words: 401

Pages: 2

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Q1. 

Sample size: 1000; sample proportion: 56%; confidence level: 95%. The construction of a confidence interval proportion procedure is based on the assumption that both np  10 and n (1- p )  a confidence interval for a population proportion is constructed by taking the point estimate ( p ˆ p^ ) plus and minus the margin of error. The margin of error is computed by multiplying a z multiplier by the standard error,   SE ( p ˆ) SE (p^) . The multiplier associated with 95% confidence interval is 1.96. Therefore, confidence interval proportion of p is 0.56±1.96 (  ) = ±3.08 

Q2. 

The z* = 1.65. 

Margin of error = (z*)(s) / sqrt n 

2 days = (1.65)(14 days) / sqrt n, now solve for n ... 

n = 133.4, always round up. 

ANSWER is 134 outside salespeople should be sampled 

Q3. 

There are seven steps in statistical hypothesis testing as listed below: 

Step 1: state the Null Hypothesis. 

The null hypothesis is the opposite of the “guess” made by the research. 

Step 2: state the Alternative Hypothesis. 

The Alternative Hypothesis is stated merely because the Null Hypothesis might be rejected for many possibilities for instance, if a null hypothesis says that every mean differs from every other mean. 

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Step 3: set α 

Step 4: Collect Data 

Data should be collected in remembrance of the significance of identifying whether the collected data is obtained through an observational or an experimental design. 

Step 5: calculate a test statistic 

F statistic is used for categorical treatment level means. 

Step 6: construct acceptance or rejection regions 

A threshold value of F is obtained from statistical tables and is known as F critical   or   Fα, which is the minimum value for the test statistic. 

Step 7: based on steps 5 and 6, draw a conclusion about H 0 

If the    F calculated from the data is larger than the Fα, then you are in the Rejection region and you can reject the Null Hypothesis with (1-α) level of confidence. 

Q4 

State the null hypothesis and the alternate hypothesis. 

Ho: u = >= 3 

Ha: u < 3 (claim) 

b) This is a left test 

c)State the decision rule. 

invT(0.05,49) = -1.6766 

Reject Ho if the test statistic is less than -1.6766 

d)Compute the value of the test static. 

t(2.75) = (2.75-3)/[1/sqrt(50)] = -0.035 

e)What is your decision regarding Ho? 

Fail to reject Ho. The test results do not support the claim 

that u < 1 

f)What is the p-value? Interpret it. 

P(t < -1.6766 when df = 49) = tcdf(-100,-0.035) = 0.0486 

g)Since the p-value is less than 5%, reject Ho. 

Q5 

The test is right tailed test 

H0: μ = 50 H1: μ ≠ 50 

Standard deviation=6 

.05 significance level 

(.05,49)=-8.333 

Since the value is more than 100%, decide Ho. 

Q6 

H0: μ ≤ 10 H1: μ > 10 

This is a left tailed test 

Standard deviation = 3 

.01 significance level] 

(.01,9)=-3.3333 

Since the value is less than 50%, reject Ho. 

Q7 

H0: μ ≥ 20 HA: μ < 20 

This is a two tailed test 

Significance level =.05 

(.05,19)=-12.5. decided. 

Q8 

It is reasonable to conclude that mean rate of return is more than 4.5%, using the .05 significance level, since the outcome is slightly above the 4.5%. 

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StudyBounty. (2023, September 14). How to Construct a Confidence Interval.
https://studybounty.com/how-to-construct-a-confidence-interval-essay

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