Statistics and Probability Answers

The percentage of physicians who are women is 28%. In a survey of physicians employed by a large university health system, 60 of 142 randomly selected physicians were women. Is there sufficient evidence at the 0.01 level of significance to conclude that the proportion of women physicians at the university health system exceeds 28%?

a. State the hypothesis and identify the claim of the researcher. b. Find the critical value(s). 

c. Compute the test value. 

d. Make a decision on the null hypothesis. 

e. Make a decision on the claim of the researcher.

The article “Evaluating Tunnel Kiln Performance” (Amer. Ceramic Soc. Bull., Aug. 1997: 59–63) gave the following summary information for fracture strengths (MPa) of n=169

n=169 ceramic bars fired in a particular kiln: x

¯

=89.10,σ=3.73

x¯=89.10,σ=3.73

a. Calculate a (two-sided) confidence interval for true average fracture strength using a confidence level of 95%

95%.

b. Suppose the investigators had believed a priori that the population standard deviation was about 4MPa

4MPa. Based on this supposition, how large a sample would have been required to estimate μ

μ to within .5 MPa with 95%

95% confidence?

_{determine the area of the region indicated.}

_{1) -1 < Z <1}

_{2) -2 < Z < 2}

The table below show Business statistics I examination marks for a class of one hundred students .

Marks 10-19 (4 student )

20-29 ( 8 student )

30-39 ( a - student )

40-49 ( 22 student )

50-59 ( 48 student )

60-69 ( b - student )

The mean score of the students was 46.5

(i) Show that the values of a and b are 12 and 6 respectively. (5marks)

(ii) Estimate the median for the above sample. (3marks)

(iii) Determine the variance and the standard deviation (4 marks)

(iv) Given that 32% of the students failed the examination, what was the cut off points.

(3 marks)

(v)Estimate the mode for this data. (3marks)

In a certain country, the true probability of a baby being a boy is 0.523. Among the next seven randomly selected births in the country, what is the probability that at least one of them is a girl?

_________ regulated the imposition and collection and distribution of levies for training purposes

Select one:

a. Employment Equity Act

b. Basic condition of employment Act

c. The Skills Development Levies Act

d. Affirmative Action

A nutritionist wants to know the population of Kindergarten pupils who eat

vegetables. A survey among 1500 kinder pupils was conducted and revealed

that 485 pupils ate vegetables. Construct the 99% confidence interval to

determine the true proportion of pupils who eat vegetables. Interpret the data.