Lab 1 Lab 2 Mean 3978333 384 Variance 1251777 127216 Observa

Lab 1

Lab 2

Mean

39.78333

38.4

Variance

125.1777

127.216

Observations

6

6

Pearson Correlation

0.986428

Hypothesized Mean Difference

0

df

5

t Stat

1.82862

P(T<=t) one-tail

0.063496

t Critical one-tail

2.015049

P(T<=t) two-tail

0.126993

t Critical two-tail

2.570578

We wish to do a quality control check on two laboratories. Samples of water are selected, and divided into two parts. One half is randomly chosen and sent to Lab 1; the other half is sent to Lab 2. Each lab is supposed to measure the impurities in the water. The results are shown above. Which is the appropriate critical value to use, if you didn\'t know the sample means before the results came back?

Solution

As we don\'t know the sample means before the results came back, then we have no idea which one is greater.

Thus, we do a two tailed test instead.

Thus, we use the t Critical two-tail,

tcrit (two tail) = 2.570578 [ANSWER]