Week 2 - Statistic: Hypothesis testing

In today's post, I would be explaining Hypothesis Testing.

So what is it???

It is used to test a claim about a parameter.

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I'll show you guys an example on how to do HYPOTHESIS TESTING. "it's pretty simple"

Our question:

"Your lab technician claims that the algal blooms caused a reduction in pH of the water. Is his claim valid? Answer this question by using the hypothesis testing method and comment on the results. Assume the populations are normally distributed and the population variances are equal. "

Step 1:

Gather: 1) No of term

2) Mean

3) Standard Deviation

Step 2:

H0: μ1 ≥ μ2 (Null Hypothesis)

Ha :μ1 < μ2 (Alternate Hypothesis )

Step 3:

α =5% ( 0.05 ) ( level of significants)

We choose 5% because its a rare event.

Step 4:

Formula for t-value:

t=((6.99-5.905)-0)/ (0.5588(1/8 + 1/8 )^1/2)

= 3.88

where

Variance s(p^2)=((8/7 x 0.58554^2)(7) + (8/7 x 0.45128^2)(7))/(16-2)

= 0.31229

sp = 0.588

Step 5:

degree of freedom (d.f) = N1+N2-2 = 8+8-2 = 14

By left tail test > T crit = - 1.761 ( from table )

We used this t-value table ------------------------------------->

Step 6:

Since T > T crit

3.88 > -1.761

Therefore, we do not reject the null hypothesis, Ho.

We can conclude that algae blooms caused a reduction in pH of water at 5% significant level.

*Special Thanks to Loke Zhao Fook for Partnering with me for this assignment

:D

written by: Kuan Ming

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