Question

Record No.	Length-mm
1	22
2	30
3	23
4	22
5	26
6	23
7	27
8	18
9	39
10	31
11	36
12	23
13	31
14	23
15	32
16	35
17	24
18	23
19	24
20	43
21	30
22	31
23	34
24	21
25	25
26	37
27	26
28	35
29	28
30	36

1. suppose you the fisher men want to use mosquito fish that are greater than 29 mm for bait, otherwise it is not worth using this lake to harvest bait fish.

a. state your research hypothesis, Ha and Ho.

Answer 1

a)

The null hypothesis, Ho: the average mosquito fish is equal to 29 mm for bait. u =29
An alternative hypothesis, h1: the avearage mosquito fish are greater than 29 mm for bait. u > 29

alpha = 5%

mean=   28.60    [Excel function used -> AVERAGE]
sd=   6.229    [Excel function used -> STDEV]
u=   29   
n=   30.00    [Excel function used -> COUNT]
alpha=   5%  

critical value, t(a,n-1) = t(0.05,30-1) = 1.699

test statistic, t = (mean-u)/(sd/sqrt(n))
t = (28.6-29)/(6.229/sqrt(30))
t = -0.3517

p-value
(1-P(T<t)
1-P(T<-0.3517)
t.dist.rt(-0.3517,30-1)
0.636197

With t(29) = -0.35, p>5%, i fail to reject Ho and conclude that the average mosquito fish is equal to 29 mm for bait.
That is there is no sufficient evidence to conclude that the average mosquito fish are greater than 29 mm for bait. u > 29