A study indicates that 18-to 24-year olds spend a mean of 135 minutes watching video on their smartphones per month. Ass

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A Study Indicates That 18 To 24 Year Olds Spend A Mean Of 135 Minutes Watching Video On Their Smartphones Per Month Ass 1 (266.51 KiB) Viewed 10 times

A study indicates that 18-to 24-year olds spend a mean of 135 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 20 minutes. Complete parts (a) through (d) below. a. What is the probability that an 18-to 24-year-old spends less than 105 minutes watching video on his or her smartphone per month? The probability that an 18-to 24-year-old spends less than 105 minutes watching video on his or her smartphone per month is 0.0668. (Round to four decimal places as needed.) b. What is the probability that an 18- to 24-year-old spends between 105 and 145 minutes watching video on his or her smartphone per month? The probability that an 18-to 24-year-old spends between 105 and 145 minutes watching video on his or her smartphone per month is 0.6247. (Round to four decimal places as needed.) c. What is the probability that an 18-to 24-year-old spends more than 145 minutes watching video on his or her smartphone per month? The probability that an 18-to 24-year-old spends more than 145 minutes watching video on his or her smartphone per month is (Round to four decimal places as needed.) ● Screen Shot 2022-07-05 at 1.39.49 AM Q ✩ A Q Search A particular manufacturing design requires a shaft with a diameter of 21.000 mm, but shafts with diameters between 20.988 mm and 21.012 mm are acceptable. The manufacturing process yields shafts with diameters normally distributed, with a mean of 21.004 mm and a standard deviation of 0.004 mm. Complete parts (a) through (d) below. Screen Shot 2022-07-05 at 1.39.15 AM 3 a. For this process, what is the proportion of shafts with a diameter between 20.988 mm and 21.000 mm? The proportion of shafts with diameter between 20.988 mm and 21.000 mm is 0.1586. (Round to four decimal places as needed.) b. For this process, what is the probability that a shaft is acceptable? The probability that a shaft is acceptable is 0.9772 (Round to four decimal places as needed.) c. For this process, what is the diameter that will be exceeded by only 5% of the shafts? The diameter that will be exceeded by only 5% of the shafts is mm. (Round to four decimal places as needed.) 1 Q Search Given a normal distribution with = 100 and = 10, complete parts (a) through (d). Click here to view page 1 of the cumulative standardized normal distribution table. Click here to view page 2 of the cumulative standardized normal distribution table. a. What is the probability that X> 80? The probability that X> 80 is 0.9772 (Round to four decimal places as needed.) b. What is the probability that X<75? The probability that X < 75 is. (Round to four decimal places as needed.)