Question

In: Statistics and Probability

A) Two arthroscopic surgeries were compared among patients suffering from osteoarthritis who had at least moderate...

A) Two arthroscopic surgeries were compared among patients suffering from osteoarthritis who had at least moderate knee pain. The lavage type has the joint flushed with fluid and no instrument is used to remove tissue; the debridement type has the joint flushed with fluid and an instrument is used to remove tissue. Knee pain scores, ranging from 0 to 100 with higher scores indicating severe pain, were obtained for patients randomly assigned to the two groups after the surgery and the results are given below:

------------Sameple Size--------Sample Mean-------Sample Standard Deviation

Lavage 11 59 24

Debridment 13 49 23

Determine a 95% confidence interval for the difference between the mean knee pain score for the lavage group and that for the debridement group

B) A test of abstract reasoning is given to a random sample of 10 students before and after completing a formal logic course. The results are shown below.

Before----------After

71 71

81 86

85 82

67 75

92 95

71 66

61 67

78 81

64 71

80 88

Determine a 95% confidence interval for the difference between the mean score after completing the course and the mean score before completing the course

C) The quality control officer collects a random sample of 100 yardsticks from the day's production run. The sample mean is 36 inches. The population standard deviation for that day’s production is σ =1 inches.

1)Find a 99% confidence interval for the mean length of all yardsticks made that day

2)The margin of error associated with the 99% confidence interval for the mean length of all yardsticks made that day is

3)You decide that margin of error in previous question is too large, and you want it to be at most 0.1 inches, what is the minimum sample size in order to obtain this margin of error with a confidence level of 99%?

Expert Solution

orchestra answered 1 year ago

Bob reported that the patients suffering from the “Mad Man Disease” who used his “magic dust”...

Bob reported that the patients suffering from the “Mad Man Disease” who used his “magic dust” elixir properly resulted in an odds-ratio = .6 relative to controls who did not use his elixir, whose probability of suffering from the “Mad Man Disease” was only p = .3. (a) Describe the meaning of the odds-ratio for elixir users in words. (b) What was the probability of suffering from the “Mad Man Disease” for the elixir group?

When the chickenpox vaccine was developed older people who had not had chickenpox were among the...

When the chickenpox vaccine was developed older people who had not had chickenpox were among the first to be able to get the vaccine. However, sometimes people have such a minor chickenpox infection that it goes unnoticed, yet still generates complete adaptive immunity. Before giving the vaccine, healthcare workers would test potential recipients to see if they already had chickenpox and had immunity to the virus. Describe how you could develop an ELISA test to determine if someone had immunity...

Two patients present with similar symptoms. Both appear to be suffering from pneumonia. One patient is...

Two patients present with similar symptoms. Both appear to be suffering from pneumonia. One patient is a 55-year-old woman with controlled hypertension and diabetes; the other is an otherwise healthy 24-year-old woman. How would the examination levels differ for the two patients? Provide your rationale for the examination level assigned. **Meet a 250 would count requirement**

Researchers compared the reaction times in people who were sleep deprived versus people who had gotten...

Researchers compared the reaction times in people who were sleep deprived versus people who had gotten a full night's rest. The following are typical data showing the reaction time scores (in seconds) for two groups (samples) of participants. ______________________________ Sleep deprived Well Rested 3 5 2 3 7 3 1 2 2 1 6 1 9 2 11 1 2 3 3 5 10 3 3 5 4 2 3 1 3 2 Compute the mean, the range, the variance,...

Cholesterol levels were collected from patients two days after they had a heart attack (Ryan, Joiner...

Cholesterol levels were collected from patients two days after they had a heart attack (Ryan, Joiner & Ryan, Jr, 1985) and are in table #3.3.10. Find the five-number summary and interquartile range (IQR) (3points), and draw a box-and-whiskers plot with all the components labeled (3 points). Extra Credit (2points): State the shape of the distribution (1 point), upper and lower fence (2 points), and if there are any outliers (1 point). 16.An experiment is rolling a fair dieand then flipping...

) Among drivers who have had a car crash in the last year, 170 were randomly...

) Among drivers who have had a car crash in the last year, 170 were randomly selected and categorized by age, with the results listed in the table below. Age Under 25 25-44 45-64 Over 64 Drivers 70 41 22 37 If all ages have the same crash rate, we would expect (because of the age distribution of licensed drivers) the given categories to have 16%, 44%, 27%, 13% of the subjects, respectively. At the 0.025 significance level, test the...

) Among drivers who have had a car crash in the last year, 120 were randomly...

) Among drivers who have had a car crash in the last year, 120 were randomly selected and categorized by age, with the results listed in the table below. Age Under 25 25-44 45-64 Over 64 Drivers 49 30 17 24 If all ages have the same crash rate, we would expect (because of the age distribution of licensed drivers) the given categories to have 16%, 44%, 27%, 13% of the subjects, respectively. At the 0.025 significance level, test the...

There were ten patients who had depression, and each patient tried a medication. Here we compare...

There were ten patients who had depression, and each patient tried a medication. Here we compare the control (no medication) and drug. Does the drug offer an improvement in depression? Table 1 shows the depression sores (0 = No depression, 30 = Strong depression), differences, and signed ranks. Test a hypothesis with Wilcoxon signed-rank test at significance level .05. Table 1: The Psychology Experiments at a Research Institution Participant 1 2 3 4 5 6 7 8 9 10 Drug...

The information on an antibiotic and bacterial-culture usage in hospitals for patients who were discharged from...

The information on an antibiotic and bacterial-culture usage in hospitals for patients who were discharged from two selected Pennsylvania hospitals were collected. Among the sampled 25 patients from Hospital 1, 7 patients received anti-biotics. And from Hospital 2, 6 patients from the sampled 30 patients received bacterial culture. Investigators are interested in assessing whether the proportions for patients receiving an antibiotic is greater than the proportion of receiving a bacterial culture while in the hospital at α=0.05. What is the...

Among drivers who have had a car crash in the last year, 170 were randomly selected...

Among drivers who have had a car crash in the last year, 170 were randomly selected and categorized by age, with the results listed in the table below. Age Under 25 25-44 45-64 Over 64 Drivers 70 41 22 37 If all ages have the same crash rate, we would expect (because of the age distribution of licensed drivers) the given categories to have 16%, 44%, 27%, 13% of the subjects, respectively. At the 0.025 significance level, test the claim...