1.) A researcher wishes to estimate the aaverage amount of money a person spends on lottery tickets each month. A sample of 80 people who play the lottery found the mean to be $22.80 and the standard deviation to be 3. Find the 95% confidence interval of the population mean. Round to two deciaml places.
2.) The data represents a sample of the number of home fires started by candles for several years. Find the 99% confidence interval for the mean number of home fires started by candles each year. 5,441 5,920 6,079 6,308 7,158 8,433 9,933 a. 5,854.8
3.) In recent survey of 110 households, 60 had central air conditioning. Find p and q, where p is the proportion of households that have central air conditiooning. What is q? Express it as a decimal number round to three decimal places.
4.) A survey of 190,000 boat owners found that 11% of the pleasure boats were named Misty. Find the 95% confidence interval of the true proportion of boats named misty. Express the upper boundary as a percent rounded to one decimal place. Please round all intermediate answers to three decimal places.
5.) A resercher wishes to estimate, with 95% confidence, the proportion of people who own a home computer. A previous study shows that 38% of those interviewed had a computer at home. The researcher wishes to be accurate within 1% of the true proportion. Find the minimum sample size necessary.
6.) A medical researcher wishes to determine the percentage of females who take vitamins. He wishes to be 99% confident that the estimate is within 3% of the true proportion. How large should the sample size be?
7.) Suppose each month, a household generates an average of 28 pounds of newspaper for garbage or recycling. Assume the standard deviation is 2 pounds. If a household is selected at random, find the probability of its generating between 22 and 30 pounds per month. Assume the variable is approximately normally distributed. Express your answer correct to the nearest hundredth of a percent.
8.) The average charitable contribution itemized per income tax return in Pennsylvania is $799. Suppose that the distribution of contributions is normal with standard deviation of $114. Find the limits for the middle 60% of contributions.
9.) Assume that the sample is taken from a large population and the correction factor can be ignored. The average public elementary school has 454 students. Assume the standard deviation of the distribution is 93. If a random sample of 36 public elementary schools is selected, find the probability that the number of students enrolled is etween 450 and 461. Give your final answer as a percent rounded to two decimal places.
10.) Find the areaunder the normal distribution curve to the right of z=1.85. Round to four decimal places.
11.) Find the area under the normal distribution curve between Z1 = -2.55 and Z2 = -0.73. Give your answer in decimal form.
12.) Suppose each month, a household generates an average of 28 pounds of newspaper for garbage or recycling. Assume the standard deviation is 2 pounds. If a household is selected at random, find the probability of its generating more than 31.1 pounds per month. Assume the variable is approximately normally distriuted. Express your answer correct to the nearest hundredth of a percent.
13.) The average salary for first-year teachers is $26,709. If the distribution is approximately normal with 0 = $2,900, what is the probability that a randomly selected first-year teacher makes less than $19,372 a year. Give your final answer as a percent rounded to two decimal places.
14.) The average charitable contribution itemized per income tax return in Pennsylvania is $723. Suppose that the distribution of contributions is normal with standard deviation of $117. Find the limits for the middle 50% of contributions.
15.) The data shown consist of the numer of games played each year in the career of a famous baseball player. Determine if the data are approximately normally distributed. 83, 148, 152, 134, 151, 152, 160, 138, 40, 161, 128, 161, 163, 145, 69, 112, 71. A. No, the data are not approximately normally distributed. B. Yes, the data are approximately normally distributed.
16.) The average number of pounds of meat that a person consumes a year is 219.6 pounds. Assume that the standard deviation is 25 pounds and the distribution is approximately normal. If a sample of 50 individuals is selected, find the probability that the mean of the sample will be less than 226 pounds per year. Round your intermediate answers to two decimal places, and round your final answer and the area bounded to four decimal places.
17.) The average yearly cost per household of owning a dog is $199.85. Suppose that we randomly select 40 households that own a dog. What's the probability that the sample mean for these 40 households is less than $208.00? Assume 0 = $26. Round your answer to two decimal places.
18.) Assume that the sample is taken from a large population and the correction factor can be ignored. The average teacher's salary is $50,000. Suppose that the distriution is normal with standard deviation equal to $6,500. What's the probability that a randomly selected teacher makes less than $46,490 a year? Give your final answer as a percent rounded to two decimal places.
19.) Assume that the sample is taken from a large population and the correction factor can be ignored. At a large publishing company, the mean age of proofreaders is 35.1 years, and the standard deviation is 3.6 years. Assume the variable is normally distributed. If a random sample of 16 proofreaders is selected, find the probability that the mean age of the proofreaders in the sample will e between 35 and 36.3 years. Give your final answer as a percent rounded to two decimal places.
20.) A study indicated that 36% of children ages 2 to 5 years had a good diet-an increase over previous years. How large a sample is needed to estimate the true proportion of children with good diets within 2% with 95% confidence?
21.) Find the Ta/2 value for the 99% confidence interval for the mean when n = 17.
22.) A study of 41 English composition professors showed that they spent, on average, 10 minutes correcting a students term paper. Find the best point estimate of the mean.
23.) Find q for the percentage 55% (use the percentage for p).
24.) The average hemoglobin reading for a sample of 24 teachers was 19 grams per 100 milliliters, with a sample standard deviation of 2 grams. Find the 99% confidence interval of the true mean. Assume that the variable is approximately normally distributed. Greater than___and less than___grams per 100 milliliters.
25.) A study of 590 people in a small city found 59 were obese. Find the 90% confidence interval of the population proportion of individuals living in the small city who are obese. Round all intermediate steps to three decimal places and final percentage to one decimal place. ___% 26.) The number of unhealthy days based on the AQI (Air Quality Index) for a random sample of metropolitan areas is shown. Construct a 98% confidence interval based on the data. Round intermediate steps and final answer to one decimal place. 60, 54, 76, 48, 79, 66, 57, 69, 52, 72. ___
27.) A pizza shop owner wishes to find the 99% confidence interval of the true mean cost of a large plain pizza. How large should the sample be if she wishes to be accurate to within %0.17? A previous study showed that the standard deviation of the price was $0.22. The shop owner needs a sample size of at least_________.
28.) A researcher wishes to estimate, with 95% confidence, the proportion of people who own a home computer. A previous study shows that 39% of those interviewed had a computer at home. The researcher wishes to be accurate within 2% of the true proportion. Find the minimum sample size necessary.