Question

A doctor discovers a particular disease and determines the life expectancy is not good. He gathers the data for his patents and posts it in the table below. The claims that the average life expectancy once the disease presents itself is less than 15 days. Check his claim and make an appropriate report about your findings Patient Days till passing

1 24

2 23

3 13

4 20

5 10

6 18

7 13

8 14

9 24

10 25

11 14

12 21

13 18

14 13

15 14

16 10

17 17

18 25

19 17

20 18

21 22

22 22

23 13

24 25

25 22

26 11

27 19

28 25

29 22

30 22

31 19

32 22

33 14

34 16

35 15

Please show presentable legible work.

I have asked this question 2 times and received different answers!!

Answer 1

Null hypothesis, ho; the average life expectancy once the disease presents itself is greater or equal to 15 days. u >= 15
Alternative hypothesis, h1: the average life expectancy once the disease presents itself is less than 15 days. u < 15

mean=   18.29    [Excel function used -> AVERAGE]
sd= sqrt(var) =   4.719    [Excel function used -> STDEV]
u=   8.00   
n=   35.00    [Excel function used -> COUNT]
alpha=   5%  

test statistic, z = (mean-u)/(sd/sqrt(n))
z = (18.2857-8)/(4.719/sqrt(35))
z = 12.8949

p-value
= P(Z<z)
= P(z<12.8949)
= NORMSDIST(12.8949)
= 1.00000

With z=12.89, p>5%, I fail to reject the null hypothesis. there is no sufficient evidence to conclude that the average life expectancy once the disease presents itself is less than 15 days. u < 15