Chapter 8, Problem 57PS

An information technology (IT) provider of cloud backup and restore solutions for small to midsize business wants to study the consequences of ransomware attacks. A random sample of 50 small to midsized companies in the United States that have experienced a ransomware attack revels the following:

Time spent dealing with the containing a ransomware incident: $\text{<mover accent="true"> X <mo> ¯ </mo> </mover>}=42\text{hours,}\text{S}\text{=}\text{8}\text{hours}$

Thirteen small a midsize companies lot customer as a result of a ransomware incident.

a. Construct a $99\%$ confidence interval estimate for the population mean time spent dealing with and containing a ransomware incident.

b. Construct a $99\%$ confidence interval estimate for the population proportion of small to midsized companies who have lost customer as a results of a ransomware incident.