Question

A hospital reported that the normal death rate for patients with extensive burns (more than 40% of skin area) has been significantly reduced by the use of new fluid plasma compresses. Before the new treatment, the mortality rate for extensive burn patients was about 60%. Using the new compresses, the hospital found that only 42 of 89 patients with extensive burns died. Use a 1% level of significance to test the claim that the mortal ity rate has dropped. What are we testing this problem? single mean single proportion (a) What is the level of significance? State the null and alternate hypotheses. Ho: 0.6; H1: 0.6 Ho: 0.6; Hi: > 0.6 Ho: p 0.6; H: p 0.6 Ho: p 0.6; H: p0.6 Ho: p 0.6; H: p> 0.6 Ho: 0.6; H1: t0.6 (b) What sampling distribution will you use? What assumptions are you making? The Student's t, since np> 5 and nq> 5 The standard normal, since np > 5 and ng 5 The Student's t, since np < 5 and nq 5 The standard normal, since np < 5 and na < 5 What is the value of the sample test statistic? (Round your answer to two decimal places.)

Answer 1

single proportion

a)

level of significance =			0.01
Ho: p =0.6;		Ho: p <0.6;

b)

the standard normal since np>5 and nq>5
value of test statistic t=(phat-p)/√((p(1-p)/n)=						-2.47

c)

p value =

0.0068

top right curve is correct

d)

at the 0.01 level, we reject the null hypothesis and conclude the data are statistically significant

e)

There is sufficient evidence at the 0.01 level,,,,,,,,,