# pbhe520 Quiz 2

 Part 1 of 1 – 58.0 Points
 Question 1 of 28 1.0 Points

If only one of several events can occur at a time, we refer to these events as being mutually exclusive events.

 A. True B. False
 Question 2 of 28 1.0 Points

The probability of rolling a 3 or 2 on a single die is an example of conditional probability.

 A. True B. False
 Question 3 of 28 1.0 Points

The probability assigned to an event that is certain not to occur is 0.0.

 A. True B. False
 Question 4 of 28 1.0 Points

A combination is an arrangement of a set of objects in which there is an order from the first through the last.

 A. True B. False
 Question 5 of 28 1.0 Points

The closer a probability is to 0, the more likely that an event will happen. The closer the probability is to 1.00, the more likely an event will not happen.

 A. True B. False
 Question 6 of 28 1.0 Points

A random variable is assigned numerical values based on the outcomes of an experiment. ( 1 points)

 A. True B. False
 Question 7 of 28 1.0 Points

A binomial distribution has a characteristic that the trials are independent, which means that the outcome of one trial does not affect the outcome of any other trial.

 A. True B. False
 Question 8 of 28 1.0 Points

For a binomial distribution, the probability of a success stays the same for each trial, but the probability of a failure varies from trial to trial.

 A. True B. False
 Question 9 of 28 1.0 Points

Some normal probability distributions have different arithmetic means and different standard deviations.

 A. True B. False
 Question 10 of 28 1.0 Points

Some normal probability distributions are positively skewed.

 A. True B. False
 Question 11 of 28 1.0 Points

The central limit theorem implies that sampling with an adequate sample size provides good estimates of population parameters.

 A. True B. False
 Question 12 of 28 1.0 Points

Based on the sampling distribution of the means and the central limit theorem, the sample mean can be used as a good estimator of the population mean, assuming that the size of the sample is sufficiently large.

 A. True B. False
 Question 13 of 28 1.0 Points

An estimate of the population mean based on a large sample is less reliable than an estimate made using a small sample.

 A. True B. False
 Question 14 of 28 1.0 Points

Generally speaking, the alternate hypothesis is set up for the purpose of either accepting or rejecting it.

 A. True B. False
 Question 15 of 28 1.0 Points

There is only one level of significance that is applied to all studies involving sampling.

 A. True B. False
 Question 16 of 28 1.0 Points

A sales representative calls on four hospitals in Westchester County. It is immaterial what order he calls on them. How many ways can he organize his calls? A. ( 1 points)

 A.A. 4 B.B. 24 C.C. 120 D.D. 37
 Question 17 of 28 1.0 Points

A C-PAP manufacturer has developed five C-PAP bases and four air blowers that could be used together to treat people with sleep apnea. How many different arrangements of base and blower can be offered?

 A.A. 5 B.B. 10 C.C. 15 D.D. 20
 Question 18 of 28 1.0 Points

A manufacturer of headache medicine claims it is 70 percent effective within a few minutes. That is, out of every 100 users 70 get relief within a few minutes. A group of 12 patients are given the medicine. If the claim is true, what is the probability that 8 have relief within a few minutes?

 A.A. 0.001 B.B. 0.168 C.C. 0.667 D.D. 0.231
 Question 19 of 28 1.0 Points

A study of a company’s practice regarding the payment of invoices revealed that an invoice was paid an average of 20 days after it was received. The standard deviation equaled five days. Assuming that the distribution is normal, what percent of the invoices were paid within 15 days of receipt?

 A.A. 15.87% B.B. 37.91% C.C. 34.13% D.D. 86.74%
 Question 20 of 28 1.0 Points

A large hospital administrators hiring firm tests job applicants who recently graduated from college. The test scores are normally distributed with a mean of 500 and a standard deviation of 50. Many hospitals considering placing a new hire in an upper level management position if the person scores in the upper 6 percent of the distribution. What is the lowest score a college graduate must earn to qualify for a responsible position?

 A.A. 50 B.B. 625 C.C. 460 D.D. 578
 Question 21 of 28 1.0 Points

A random sample of 85 group leaders, supervisors, and similar personnel revealed that a person spent an average 6.5 years on the job before being promoted. The population standard deviation was 1.7 years. Using the 0.95 degree of confidence, what is the confidence interval for the population mean?

 A.A. 6.99 and 7.99 B.B. 4.15 and 7.15 C.C. 6.14 and 6.86 D.D. 6.49 and 7.49
 Question 22 of 28 1.0 Points

A sample of 20 is selected from the population. To determine the appropriate critical t-value what number of degrees of freedom should be used?

 A.A. 20 B.B. 19 C.C. 21 D.D. 25
 Question 23 of 28 3.0 Points

Describe the difference between H0 and H1.

The Null and Alternate Hypothesis statements must oppose each other. The null hypothesis is a statement of no difference and the alternative hypothesis contradicts the null hypothesis.

 Comment: okay
 Question 24 of 28 3.0 Points

In most clinical research studies, would you expect the researcher to use a one or a two tailed hypothesis test. Explain your answer in detail.

There are two different types of tests that can be performed. A one-tailed test looks for an increase or decrease in the parameter whereas a two-tailed test looks for any change in the parameter (which can be any change- increase or decrease).

Two tailed tests are easier to prove, so it is for that very reason that a researcher would want to use a one tailed test whenever possible because it makes for a stronger statement

 Comment: ok
 Question 25 of 28 3.0 Points

Selecting a Level of Significance. For each of the following situations, choose a level of significance (alpha) appropriate to the seriousness of the potential error involved should the null hypothesis be rejected when it is actually true. Explain in detail your choice of alpha. 25. You wish to decide on whether a new treatment for pancreatic cancer, known to be a fatal disease, is superior to the standard treatment.

99% because it is a life-and-death decision.

 Comment: ok
 Question 26 of 28 3.0 Points

Selecting a Level of Significance. For each of the following situations, choose a level of significance (alpha) appropriate to the seriousness of the potential error involved should the null hypothesis be rejected when it is actually true. Explain in detail your choice of alpha. 26. The claim is made that the mean income for families of size four is greater than 40,000 dollars.

90 or 95 should be suitable as the answer is not critical.

 Comment: ok
 Question 27 of 28 12.0 Points

It is determined that the 100 subjects have a sample mean serum cholesterol level of 217 and the sample standard deviation is 39. If the desirable serum cholesterol level is set at 200, would you have concerns about elevated serum cholesterol level in this sample? Use alpha = .05 Step 1 Step 2 Step 3 Step 4 Hint: Here you should answer the questions based on the steps 1-3.

Step 1

Ho: u = 200

Ha: m > 200 (claim)

—————-

Step 2

test stat: t = (217-200)/[39/sqrt(100)] = 17/[3.9] = 4.36

——–

Step 3 p-value = P(t > 4.36 when df = 99) = 0.0000159

Step 4 Since the p-value is less than 55, reject Ho.

The test results support the claim the at the tested level is elevated

and you should be concerned.

 Comment: okay
 Question 28 of 28 12.0 Points

A researcher wanted to determine whether a program for routine cholesterol screening for college men would identify high serum cholesterol levels. The researcher decided that above 200 would be high. Twenty students were randomly selected for cholesterol screening, and the results were given below. Is there any evidence that asymptomatic college men have elevated serum cholesterol values? Would a large-scale screening program be warranted? Use alpha = .05 160 210 200 230 210 150 220 190 210 220 160 220 240 180 200 200 210 170 180 220 You should be able to confirm that the mean is 199 and standard deviation is = 25.11 Step 1 Step 2 Step 3 Step 4 Hint: Here you should answer the questions based on the steps 1-3.

x-bar = 199

s = 25.11

z(199) = (200-199)/[25.11/sqrt(20)] = 1/5.59 = 0.1789

p-value = P(z > 0.1789) = normalcdf(0.1789,100) = 0.4290

Since the p-value is greater than 5% a

screening program wouild not be warranted.

——

 Comment: Where is the hypotheses statements: See below for consideration: Step 1: State the hypotheses: H0: population mean serum cholesterol level, µ ≤ 200 versus H1: population mean serum cholesterol level, µ > 200 Step 2: n=20, µ=200, xbar = 199 tstat = (µ -x) / [s/sqrt(n)] = (199-200)/[25.11/sqrt(20)] = – 0.18 Step 3: t(19,0.18) Corresponding p-value > 0.25 (From Table C) Reject if P < 0.05 Step 4: At the 5% level of significance we do not reject the null hypothesis and conclude that the sample serum cholesterol level is 200.