According to a marketing website. adults in a certain country average 49 minutes

Question

According to a marketing website. adults in a certain country average 49 minutes per day on mobile devices this year Assume that minutes per day on mobile devices follow the normal distribution and has a standard deviation of 10 minutes. Complete parts a through c below What is the probability that the amount of time spent today on mobile devices by an adult is less than 58 minutes? (Round to four decimal places as needed) What is the probability that the amount of time spent today on mobile devices by an adult is between 30 and 46 minutes? Round to four decimal places as needed) What amount of time spent today on mobile devices by an adult represents the 80th percentile? An amount of time of minutes represents the 80th percentile (Round to two decimal places as needed)

Explanation / Answer

Solution:-

As gven in the question that minutes per day on mobile devices follows normal distribution. So, we can use online normal distribution calculator to solve this question.

(a)

Normal random variable (x) = 58

Mean = 49

Standard deviation = 10

Cumulative probability: P(X < 58) = 0.8159

(b) For, the same mean and standard deviation,

P(30 < X < 46) = 0.3534

(c) For, the same mean and standard deviation

For 80th percentile corresponding z value is 0.8416.

Therefore, 79.99 minutes represent the 80th percentile.

Related Questions

Navigate

• Browse (All)
• Browse A
• Subjects

---

---

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