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 10 minutes. What is the probability that an 18- to 24-year-old spends less than 130 minutes watching video on his or her smartphone per month? (please sh show me how you got the answer)

The latest available data showed health care spending were $8086 per person in the United States (17.6% of GDP). Use $8086 as the population mean and $2500 as the population standard deviation. Suppose a survey firm will take a sample of 100 people to investigate their health care spending What is the sampling distribution of the mean amount of health care spending for the sample of 100 people? (i.e. shape, mean, sd) What is the probability the sample mean will be within +$200 of the population mean?

According to the latest internet usage survey of college students, the amount of time spent on social media per day is normally distributed with a mean equal to 210 minutes  and a standard deviation of 45 minutes.  Based on this survey, find the probability that the amount of time spent on social media by college students is between 150 and 300 minutes per day.  Round answer to 4 decimal places.

In 2021, the CDC estimated the mean height of U.S. women aged 20 years old and over was 63.5 inches with a standard deviation of 5.2 inches. (https://www.cdc.gov/nchs/fastats/body-measurements.htm) What is the expected mean for a sample of 150 women? What is the standard deviation of the mean for a sample of 150 women? What is the probability of 150 women having a sample mean below 60 inches? What is the probability of 150 women having a sample mean above 65 inches? What is the probability of 200 women having a sample mean below 60 inches? Notice the change in sample size. What is the probability of 200 women having a sample mean above 65 inches?