Statistical Analysis including all steps please eg hypothesi

Statistical Analysis [including all steps please, e.g. hypothesis, assumptions,conclusion... ]

Solution

First find mean std deviation of each sample from the data given

H0: mu1 = mu2

Ha: mu1 not equals mu2

Two tailed hypothesis test

As sample size is 12 t test is used.

Mean difference =-1.834

stddev diff = 3.0943

Assuming equal variances, df = 22

Pooled Standard Deviation: 7.5794
Pooled DF: 22
95% Confidence Interval for the Difference ( -8.2513 , 4.5833 )
T-Value -0.5927

p value =0.5594

As p value > alpha at 0.05 we accept null hypothesis

There is no difference between downstream and upstream.

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With the same mean let us have sample size as 20,30,50,80

i) n =20

t difference = -0.765

p value =0.2234

Difference not significant.

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ii) n=30

t-difference: -0.937

p value = 0.3504

Diff not significant.,

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iii) n=50

t-difference: -1.21

p value = 0.2296

Diff not significant.

iv) n = 80

t-difference: -1.53

p value =0.1288

Difference not significant as p > alpha

	N	Mean	StDev	SE Mean
Sample 1	12	14.583	7.9253	2.288
Sample 2	12	16.417	7.2169	2.083