Question

Information: A hypothesis of clinical interest was that vitamin C prevents the common cold. A study...

Information: A hypothesis of clinical interest was that vitamin C prevents the common cold. A study is organized to test this hypothesis using 20 participants. In the study, 10 were randomly allocated to receive vitamin C capsules and 10 were randomly allocated to receive placebo capsules. The number of colds over a 12-month period for each participant is recorded. The samples were randomly selected, and the populations are approximately normally distributed. Population variances are unknown but assumed to be approximately equal.

In the problems below, you will answer the following question: Is the mean number of colds different between those who take vitamin C and those who do not take vitamin C? (use an α of 0.05)

The average number of colds

Standard deviation

Vitamin C group:

3.3

1.57

Placebo group:

5.7

1.34


  1. State the null hypothesis using sentences and symbols (2 pts):


  1. State the alternative hypothesis using sentences and symbols(2 pts):

  1. What is the appropriate test for this situation? Explain your response! (If applicable, please indicate whether the test is one or two-sided and whether it is a one or two-sample test) (2 pts)

  1. What are the degrees-of-freedom (if applicable)? (1 pt)

  1. What are the critical values? Note: For two-sided tests, there are two critical values: a positive critical value and a negative critical value. You may use a table or an online calculator to obtain your critical value(s). (3pts)

  1. Upon running the calculations, a test statistic is equal (– 3.68). What is your statistical decision – reject the null or fail to reject the null hypothesis? Why? Explain in one paragraph(5 pts)

Homework Answers

Know the answer?
Your Answer:

Post as a guest

Your Name:

What's your source?

Earn Coins

Coins can be redeemed for fabulous gifts.

Not the answer you're looking for?
Ask your own homework help question
Similar Questions
Part 1: Information: A hypothesis of clinical interest was that vitamin C prevents the common cold....
Part 1: Information: A hypothesis of clinical interest was that vitamin C prevents the common cold. A study is organized to test this hypothesis using 20 participants. In the study, 10 were randomly allocated to receive vitamin C capsules and 10 were randomly allocated to receive placebo capsules. The number of colds over a 12-month period for each participant is recorded. The samples were randomly selected, and the populations are approximately normally distributed. Population variances are unknown but assumed to...
In the 1980’s, a clinical trial was conducted to determine if taking an aspirin daily reduced...
In the 1980’s, a clinical trial was conducted to determine if taking an aspirin daily reduced the incidence of heart attacks. Of 22,071 medical doctors participating in the study, 11,037 were randomly assigned to take aspirin and 11,034 were randomly assigned to the placebo group. Doctors in this group were given a sugar pill disguised to look like aspirin. After six months, the proportion of heart attacks in the two groups was compared. Only 104 doctors who took aspirin had...
Low-birth-weight babies are at increased risk of respiratory infections in the first few months of life...
Low-birth-weight babies are at increased risk of respiratory infections in the first few months of life and have low liver stores of vitamin A. In a randomized, double-blind experiment, 55 low-birth-weight babies were randomly divided into two groups. Subjects in group 1 (treatment group, n1 = 30) were given 25,000 IU of vitamin A on study days 1, 4, and 8; study day 1 was between 36 and 60 hours after delivery. Subjects in group 2 (control group, n2 =...
A study was performed to test the effectiveness of turmeric (a spice common in Indian and...
A study was performed to test the effectiveness of turmeric (a spice common in Indian and Indonesian cooking) in the treatment of knee arthritis. There were 107 patients in the study. A random sample of 55 of these patients were placed in the “turmeric” group, and the remaining 52 in the “control” group. Patients in the control group received a standard treatment of Ibuprofen. All patients were timed going up and down a flight of stairs at the end of...
In the largest clinical trial ever? conducted, 401,974 children were randomly assigned to two groups. The...
In the largest clinical trial ever? conducted, 401,974 children were randomly assigned to two groups. The treatment group consisted of? 201,229 children given the Salk vaccine for? polio, and the other? 200,745 children were given a placebo. Among those in the treatment? group, 33 developed? polio, and among those in the placebo? group, 115 developed polio. If we want to use the methods for testing a claim about two population proportions to test the claim that the rate of polio...
In the largest clinical trial ever​ conducted, 401,974 children were randomly assigned to two groups. The...
In the largest clinical trial ever​ conducted, 401,974 children were randomly assigned to two groups. The treatment group consisted of​ 201,229 children given the Salk vaccine for​ polio, and the other​ 200,745 children were given a placebo. Among those in the treatment​ group, 33 developed​ polio, and among those in the placebo​ group, 115 developed polio. If we want to use the methods for testing a claim about two population proportions to test the claim that the rate of polio...
1a) A researcher conducts an independent-measures study to examine how the brain chemical serotonin is related...
1a) A researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there...
A random selection of volunteers at a research institute have been exposed to a typical cold...
A random selection of volunteers at a research institute have been exposed to a typical cold virus. After they started to have cold symptoms, 10 of them were given multivitamin tablets daily which contain 3 grams of vitamin C and various other vitamins and minerals. The remaining 10 volunteers were given placebo tablets. For each individual, the length of time taken to recover from cold is recorded. At the end of the experiment following data are obtained: Days to recover...
An experiment was planned to compare the mean time (in days)required to recover from a...
An experiment was planned to compare the mean time (in days) required to recover from a common cold for persons given a daily dose of 4 milligrams (mg) of vitamin C, μ2, versus those who were not, μ1. Suppose that 32 adults were randomly selected for each treatment category and that the mean recovery times and standard deviations for the two groups were as follows. No Vitamin Supplement 4 mg Vitamin C Sample Size 32 32 Sample Mean 6.5 5.5...
_____11) If the null hypothesis is that the population mean is equal to 150 and a...
_____11) If the null hypothesis is that the population mean is equal to 150 and a sample                 mean of 113 gave significant support against the null hypothesis, which of the                 following sample means would be certain to give support against the null                  hypothesis.     a) 114                              b.) 122                   c.) 264               d.) 112 _____12) If the p-value is less than the significance level, you would .      a.) reject the null hypothesis         b.) accept...