In India, four-year-olds average three hours a day unsupervised. Most of the unsupervised children live in rural areas, considered safe. Suppose that the standard deviation is 1.5 hours and the amount of time spent alone is normally distributed. We randomly survey one Indian four-year-old living in a rural area. We are interested in the amount of time the child spends alone per day. 90% of the children spend at least how long per day unsupervised? (Round your answer to two decimal places.)

A report about how American college students manage their finances includes data from a survey of college students. Each person in a representative sample of 793 college students was asked if they had one or more credit cards and if so, whether they paid their balance in full each month. There were 500 who paid in full each month. For this sample of 500 students, the sample mean credit card balance was reported to be $825. The sample standard deviation of the credit card balances for these 500 students was not reported, but for purposes of this exercise, suppose that it was $195. Is there convincing evidence that college students who pay their credit card balance in full each month have a mean balance that is lower than $907, the value reported for all college students with credit cards? Carry out a hypothesis test using a significance level of 0.01. In USE SALT State the appropriate null and alternative hypotheses. Но: и 907 Но: и 3D 907 На: и # 907 a' O Ho: µ = 907 H: H 907 Н: и…

A report about how American college students manage their finances includes data from a survey of college students. Each person in a representative sample of 793 college students was asked if they had one or more credit cards and if so, whether they paid their balance in full each month. There were 500 who paid in full each month. For this sample of 500 students, the sample mean credit card balance was reported to be $825. The sample standard deviation of the credit card balances for these 500 students was not reported, but for purposes of this exercise, suppose that it was $195. Is there convincing evidence that college students who pay their credit card balance in full each month have a mean balance that is lower than $907, the value reported for all college students with credit cards? Carry out a hypothesis test using a significance level of 0.01. Find the test statistic and P-value.

due to the increasing price of apartments each year, houston chronicle reported that rent of 1 bed 1 bath apartments in houston and suburbs is $1200 with standard deviation of $500. suppose claire decided to take 20 different random samples from the different houston areas. in how many samples would she expect to get the price to be more that $1100?

Adult Great Basin rattlesnakes have a mean length of 31 inches and a standard deviation of 4.7 inches; the length of adult Southern Pacific rattlesnakes is also 31 inches on average, but with a standard deviation of 7.05 inches. Both species have lengths that follow a normal distribution. You select a random sample of 36 Great Basin rattlesnakes and 100 Southern Pacific rattlesnakes. Which is more likely be shorter than 28.65 inches? O a. The sample mean length of the Southern Pacific rattlesnakes Ob. Not enough information is provided; it depends. O c. Both sample means are equally likely to be more than 33.35 inches long O d. The sample mean length of the Great Basin rattlesnakes

Salaries for teachers in a particular elementary school district are normally distributed with a mean of $45,000 and a standard deviation of $6,200. We randomly survey ten teachers from that district. Find the 80th percentile for the sum of ten teachers' salary. (Round your answer to the nearest whole number.)

Six different​ second-year medical students at Bellevue Hospital measured the blood pressure of the same person. The systolic readings​ (in mmHg) are listed below. Find the​ range, variance, and standard deviation for the given sample data. If the​ subject's blood pressure remains constant and the medical students correctly apply the same measurement​ technique, what should be the value of the standard​ deviation?

A researcher gathered data on five randomly selected individuals from a data set. The ages are 25, 27, 20, 21, and 29. What is the standard deviation for respondent's age?

A newspaper article reported that people spend a mean of 6.5 hours per day watching TV, with a standard deviation of 2.0 hours.  A psychologist would like to conduct interviews with 10% of the population who spend the most time watching TV.  She assumes that the daily time people spend watching TV is normally distributed.  At least how many hours of daily TV watching are necessary for a person to be eligible for the interview?

A published study says that 95 percent of American children are vaccinated against measles, with a standard deviation of 1.5 percent. You draw a sample of 100 children from your community and check their vaccination records, to see if the vaccination rate in your community is the same as the nationalaverage. What distribution will you use for this test, and why?