A sample of 50 cotton threads shows the mean breaking strength to be 220 grams and the sample standard deviation to be 12 grams. What is the 95% confidence interval for the standard deviation of breaking strength of the thread.

The confidence interval for this case would be (216.589, 223.411)

Step-by-step explanation:

Information given

represent the sample mean

population mean

s=12 represent the sample standard deviation

n=50 represent the sample size  

Confidence interval

The confidence interval for the mean is given by the following formula:

  (1)

The degrees of freedom are given by:

The Confidence level is 0.95 or 95%, the significance is and , the critical value for this case is

And replacing we got:

The confidence interval for this case would be (216.589, 223.411)

-10i^2-4i

step-by-step explanation:

evaluate for p=2,q=5i

(2−4)(2+5i)i

(2−4)(2+5i)i

=−10i2−4i

the expression (1.26)2t reveals the approximate rate of increases in the number of plants semiannually.

hope this : )