Unit 7 Notes 3 Margin of Error T-test

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Fill in the Blanks

What is the margin of error for this problem?

(hint: "within

mil...")

Multiple Choice

What is the z* for this problem?

• 2.576

• 1.96

• 1.645

• 1

Fill in the Blanks

What is the population standard deviation given?

Multiple Choice

Plug in all three variables we just identified. Use algebra to solve for n.

n = ____

• 0.5102

• 9.8

• 96

• 97

Multiple Choice

State the variable we are studying in this question.

• μ_d = mean difference in blood sugar levels between the current medication and the new medication (current – new)

• μ_d = mean blood sugar levels from the current medication

• μ_d = mean blood sugar levels from the new medication

• μ_d = mean levels of Type 2 Diabetes

Multiple Choice

State the hypotheses for this question.

• H₀ : μ = 0

  H_a : μ > 0

• H₀ : μ = 0

  H_a : μ < 0

• H₀ : μ = 0

  H_a : μ ≠ 0

• H₀ : μ < 0

  H_a : μ > 0

Multiple Choice

Let's do a One Sample T-test for Means.

Enter the list of differences in L1 in your calculator. What is $$\overline{x}_d$$ _?

• 0

• 0.156

• 0.234

• 0.844

Multiple Choice

What is the standard deviation of the sample?

• 0.263

• 0.737

• 0.123

• 0.554

Multiple Choice

Let's use a T-test. (Stat > Test > 2.T-test)

What is t?

• 1.883

• 2.104

• 1.692

• 2.373

Multiple Choice

Using the same calculator calculation, what is p?

• 0.0179

• 0.0157

• 0.0132

• 0.005

Multiple Choice

Now that you have all the relevant information, what is your conclusion?

• Reject the null

• Fail to reject the null

Now let's practice!

the next questions you will complete at your own pace

Multiple Choice

A sample of n students were asked for the average amount of money they spend in a day. The data resulted in a mean of $5.50 with a standard deviation of $2.45. If the margin of error was $0.31, how many students were in the sample? Round to the nearest whole student

• 250

• 16

• 100

• 500

Multiple Choice

A researcher wishes to estimate, within $25, the true mean amount of postage a community college spends each year. The standard deviation is known to be $80. If she wishes to be 95% confident in her estimate of the true mean amount of postage, how large a sample is necessary? Round to the nearest whole number

• 41

• 25

• 80

• 200

Multiple Choice

Suppose a department store wants to estimate within 2 years the true mean age of the customers in its contemporary apparel department. The department store manager assumes a standard deviation of 7.5 years. How large a sample is required to estimate the true mean age with 95% confidence?

Round to the nearest whole number

• 56

• 112

• 420

• 224

Multiple Choice

Complete the following statement about the change in size.

If you increase the size of your sample, the ME will . . . .

• increase

• decrease

• stay the same

Multiple Choice

For a class project, a student in a statistics class surveys the monthly rent for 32 unfurnished one-bedroom apartments in Boston and finds the mean monthly rent to be $1400 with a standard deviation of $220.

Find the 95% confidence interval for the population mean Round to the nearest hundredth

• [1322.22, 1477.78]

• [1395.69, 1404.31]

• [1211.22, 1588.78]

• [905.03, 1894.97]

Multiple Choice

A one sample t-test is conducted on Ho : μ = 81.6. The

sample has a sample mean = 84.1 , s = 3.1, n = 25, and α = .01.

• Reject Ho

• Reject Ha

• Fail to reject Ho

• Fail to reject Ha