Answer:
(a) z = -1.53 --> P(x<z) = 0.0630
(b) z = -1.151 --> P(x<z) = 0,0655
(c) z = -0.63 --> P(x<z) = 0,2643
Step-by-step explanation:
To know the area that lies to the left, equal to P(x<z), the best way is to look at tables of standard normal curve.
(a) z = -1.53 --> P(x<z) = 0.0630
(b) z = -1.151 --> P(x<z) = 0,0655
(c) z = -0.63 --> P(x<z) = 0,2643
Answer:
Now we just take square root on both sides of the interval and we got:
And the best option would be:
A. 2.2 < σ < 2.8
Step-by-step explanation:
Information provided
represent the sample mean
population mean
s=2.4 represent the sample standard deviation
n=83 represent the sample size
Confidence interval
The confidence interval for the population variance is given by the following formula:
The degrees of freedom are given by:
The Confidence is given by 0.90 or 90%, the value of and
, the critical values for this case are:
And replacing into the formula for the interval we got:
Now we just take square root on both sides of the interval and we got:
And the best option would be:
A. 2.2 < σ < 2.8