A study indicates that 18- to 24- year olds spend a mean of 115 minutes watching

Question

A study indicates that 18- to 24- year olds spend a mean of 115 minutes watching video on their smartphones per month. Assume that the amount of time watching video on a smartphone per month is normally distributed and that the standard deviation is 10 minutes. Complete parts (a) through (d) below.

a. What is the probability that an 18- to 24-year-old spends less than 100 minutes watching video on his or her smartphone per month?The probability that an 18- to 24-year-old spends less than 100 minutes watching video on his or her smartphone per month is nothing.

(Round to four decimal places as needed.)

Explanation / Answer

Mean ( u ) =115
Standard Deviation ( sd )=10
Normal Distribution = Z= X- u / sd ~ N(0,1)                  
a.
P(X < 100) = (100-115)/10
= -15/10= -1.5
= P ( Z <-1.5) From Standard Normal Table
= 0.0668                  

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.