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Chapter 6: Binomial Distributions
Chapter 7: Normal Distributions
SURPRISE!!!
Chapter 9: Confidence Intervals
Chapter 10: Hypothesis Tests
100
Which of the following are necessary assumptions for using the normal approximation to approximate a binomial? 1. Both np and nq must be at least 10 2. The sample size must be less than 10% of the population 3. The sample should be an SRS
#1
100
The weights of commercially raised chickens are normally distributed with mean 1387 grams and standard deviation 161 grams. What is the probability a randomly selected chicken weighs more than 1600 grams?
.09292
100
Suppose it is known that 52% of American Adults have a CPR certificate. A random sample of 310 American adults are selected. How do you describe the proportion of adults in the sample who have an organ donor card? A. X~AN (.51, .987) B. p^~AN(.52, .0284) C. X~B (.52, .0314) D. p^~AN (52, 310)
B
100
Which of the following will decrease the margin of error of a confidence interval? (More than one may apply) 1. Increase the confidence level 2. Decrease the confidence level 3. Increase the sample size 4. Decrease the sample size
What is #2 and #3?
100
What is the level of significance of the hypothesis test if it uses a 96% confidence interval to state its claim?
what is .04?
200
A consumer organization inspecting new trucks found that 75% had no defects,13% had one defect, 7% had two defects, 5% had three defects. Calculate the expected number of appearance defects in a new truck.
.42
200
Scores on an I.Q. test are normally distributed, with a standard deviation of 20. If only 12% of the scores are above 125, what is the mean of the distribution?
Mean is 96.5
200
The hypothesis tests are Ho: p=.7 and Ha: p> .7 The z=2.46, What is the p-value?
.0069
200
A 95% confidence interval was calculated to be (.0633, .0691). What is the point estimate and margin of error?
Point Estimate: .0662 Margin of Error:.0029
200
What is the power in a hypothesis test? A. Probability we fail to reject the null when it is false B. Probability we reject he null when it is true C. Probability we reject the null hypothesis when it is false D. The probability we fail to reject the null hypothesis when it is true.
C
300
It is known that 45% of college students work full time. If we randomly select 23 college students, What is the probability exactly 14 work full time?
.05255
300
The amount of time an adult spends on the internet follows a normal distribution with a mean of 8.2 and standard deviation of .71 hours. What is the probability a randomly selected adult spends less than 5.6 hours using the internet?
.000125
300
A sample of votes show that 61% of eligible voters did actually vote. A 96% confidence interval is calculated, (.671, .728). If we test the claim that people do not lie about voting, what can we conclude?
Since 0.61 does not fall in the confidence interval, evidence indicates people lie about voting.
300
A random survey of 375 women found 294 said they change their nail polish once a week. What is a 90% confidence interval for the population proportion of women who change their nail polish once a week?
(.749, .819)
300
A claim of 9% of children under 18 have asthma. If a random sample of 150 children, found that 5% have asthma. Do we have enough evidence? Identify the null and alternative hypothesis.
Ho: p=.09 Ha: p=/.09
400
Starbucks wanted to know how popular their holiday BOGO special would be. If the randomly take 36 people's orders, and on average 65% of orders are BOGO. What is the probability more than half of those orders are BOGO?
.9543
400
Assume the weight of printer paper is a normal distribution with a mean of 47 pounds and the standard deviation is 8 lbs. Use the Empirical Rule to estimate the percentage of printer paper bundles weighing between 31 and 55 lbs?
81.5%
400
The USDA contamination limit for chicken is 20%. A meat inspector claims that the chicken produced at a company exceeds the contamination limit. A hypothesis test is conducted and shows that the level of contamination is greater than 20%. What is a Type 1 error in this situation?
Conclude that the level of chicken contamination at the company is greater than 20%, when it is actually not more than 20%.
400
A researcher wishes to estimate the population proportion of U.S. adults overweight. They wish to estimate the proportion to within 7.5% with 95% confidence. How many individuals should be included in the sample?
171 people
400
National data suggests that 44% of workers invest in retirement accounts. A hypothesis test is conducted to test this claim and the p-value= .039. What is the correct conclusion and its reason if a significance level of .01 is used?
Fail to reject the null hypothesis because the p-value is larger than the sig. level of the test.
500
A survey of workers found that 35% are college graduates. A random sample of 75 workers is selected. What is the probability at least 31 are college graduates?
.1519
500
Cherry trees have heights normally distributed with mean 112 inches and standard deviation of 14 inches. A scientists wants to study the tallest 4% of the trees to determine whether they have a certain gene that allows them to grow taller. To do this she needs to study all of the trees above what height (in inches)?
136.5
500
A researcher creates the following 98% CI for the true proportion of children who receive a flu shot: (.72, .80). The previous year the proportion was .68 and the researcher conducted a hypothesis test. Which of the following statements has to be true? A. The researcher would reject the null at sig. level =.01 B. The researcher would reject the null at the sig. level=.02 C. The researcher would fail to reject the null at sig. level=.02
B
500
A study shows that 35% of a sample of 425 students at SDSU like to study at the student union. What is a 99% confidence interval of the study described above?
(.2901, .4102)
500
A magazine considering the launch of an online version. They will on launch of it is convinced that more than 25% of the readers will subscribe. A hypothesis test calculated a z=1.72. When testing at the 1% significance level what is the most appropriate conclusion?
There is not sufficient evidence to conclude that more than 25% of readers would subscribe to the online magazine.