Statistics and Probability Answers

a sample of 91 circuits from a large normal population has a mean resistance of 2,4 ohms. if the population standard deviation is 1.5 ohms, determine a 95% confidence interval for the true mean resistance of the population. (hint: critical value is 1.96) what is the lower limit value

A short-term insurance company receives, in each working day, three motor vehicle claims. Assume that the daily claims rate follow a Poisson process. How likely is it that either eight or nine motor vehicle claims will be received in two working days? Express your answer to 4 decimal places.

Chan et al. (A-9) developed a questionnaire to assess knowledge of prostate cancer. There was a total of

36 questions to which respondents could answer “agree,” “disagree,” or “don’t know.” Scores could range from 0 to 36. The mean scores for Caucasian study participants was 20.6 with a standard deviation of 5.8, while the mean scores for African-American men was 17.4 with a standard deviation of 5.8. The number of Caucasian study participants was 185, and the number of African-Americans was 86.

 Q waves on the electrocardiogram, according to Schinkel et al. (A-15), are often considered to be

reflective of irreversibly scarred myocardium. These researchers assert, however, that there are some indications that residual viable tissue may be present in Q-wave-infarcted regions. Their study of 150 patients with chronic electrocardiographic Q-wave infarction found 202 dysfunctional Q-wave regions. With dobutamine stress echocardiography (DSE), they noted that 118 of these 202 regions were viable with information from the DSE testing. Construct a 90 percent confidence interval for the proportion of viable regions that one might expect to find a population of dysfunctional Q-wave regions.

 The objective of a randomized controlled trial by Adab et al. (A-19) was to determine whether providing

women with additional information on the pros and cons of screening for cervical cancer would increase the willingness to be screened. A treatment group of 138 women received a leaflet on screening that contained more information (average individual risk for cervical cancer, likelihood of positive finding, the possibility of false positive/negative results, etc.) than the standard leaflet developed by the British National Health Service that 136 women in a control group received. In the treatment group, 109 women indicated they wanted to have the screening test for cervical cancer while in the control group, 120 indicated they wanted the screening test. Construct a 95 percent confidence interval for the difference in proportions for the two populations represented by these samples

the number of typographical errors in a bcom hons dissertation is poisson distributed with a mean of 2,9 per 100 pages. if 100 pages of the dissertation are selected randomly, what is the probability that there are no typographical errors?

a surgery has a success rate of 75%. suppose that the surgery is performed on four patients. what is the probability that the surgery is successful on exactly 2 patients?

A farmer believes that using organic fertilizers on his plants will yield greater income. His

average income from the past was P300, 000.00 per year.

there are 3 red pens, 4 blue pens and 5 black pens in a box, Sameena picks a pen at random from the box. What is the probability that the pen is NOT black

Consider all samples of size of 5 from the population

2,5,7,9,10,11,12