The average zinc concentrations recovered from a random sample of zinc measurements in 22 di erent locations was found to be 2.6 grams per milliliter. Assume that the variance for zinc measurements is known to be 0.09 grams per milliliter squared. Calculate and interpret a 90% con dence interval for the overall average zinc concentration.

Complete Question

The average zinc concentrations recovered from a random sample of zinc measurements in 22 different locations was found to be 2.6 grams per milliliter. Assume that the variance for zinc measurements is known to be 0.09 grams per milliliter squared. Calculate and interpret a 90% confidence interval for the overall average zinc concentration.

The 90% confidence interval for the overall average zinc concentration [2.59, 2.61]

Step-by-step explanation:

From the question, we are given that following:

Mean = 2.6g/ml

Variance = 0.09(g/ml)²

Standard deviation = √variance

= √0.09

= 0.3g/ml

n = number of sample = 22

Note that our sample size is small because it is less than 30, so instead of using the z score of a 90% confidence interval, we apply the t score of a 90% confidence interval.

First we find the degrees of freedom = n - 1

= 22 - 1 = 21

T score using degrees of freedom from 90% confidence interval = 1.721

Hence, the formula for Confidence Interval =

Mean ± t × standard deviation /√n

2.6 ± 1.721 × 0.3/√22

2.6 ± 1.721 × 0.0639602149

2.6 ± 0.011007553

= 2.6 - 0.011007553

= 2.588992447

≈ 2.59

= 2.6 + 0.011007553

= 2.611007553

≈ 2.61

Therefore, the 90% confidence interval for the overall average zinc concentration [2.59, 2.61]

see below

step-by-step explanation:

7.   there are 10 data points in the set.   the middle point is between 5 and 6.   the middle point in the top half is 8   and the middle point in the bottom half is 3. to find the iqr , take point 8 and subtract point 3

mid term   point 8 = 100   point 3 = 88

iqr = 100-88 = 12

final   point 8 = 93   point 3 = 78

iqr = 93 - 78 = 15

the final has the greatest iqr

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2.   there is no way to tell what the means are from the box and whisker plots.  

he sells x mount because thats eqivilqant to the maz and then divided into quarters

step-by-step explanation: