Answer:
Step-by-step explanation:
We want to determine a 95% confidence interval for the mean lead concentration of sea water samples
Number of samples. n = 6
Mean, u = 0.903 cc/cubic meter
Standard deviation, s = 0.0566
For a confidence level of 95%, the corresponding z value is 1.96. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean +/- z ×standard deviation/√n
It becomes
0.903 +/- 1.96 × 0.0566/√6
= 0.903 +/- 1.96 × 0.0566/2.44948974278
= 0.903 +/- 0.045
The lower end of the confidence interval is 0.903 - 0.045 =0.858
The upper end of the confidence interval is 0.903 + 0.045 =0.948
Therefore, with 95% confidence interval, the mean lead concentration of the sea water is between 0.858 cc/cubic meter and 0.948 cc/cubic meter
