# The average production of peanuts in a certain state is 3,136 pounds per acre

Q4: The average production of peanuts in a certain state is 3,136 pounds per acre. A new plant food has been developed and it is tested on 74 individual plots of land. The mean yield with the new plant food is 3,385 pounds of peanuts per acre with a standard deviation of 449 pounds. At a=0.05 can one conclude that the average production has increased, find the critical value.

Q7: A state executive claims that the average number of acres in Pennsylvania state parks is less than 2,399 acres. A random sample of 5 parks is selected, and the number of acres is shown (950, 1147, 728, 6784, 622). At a=0.01, find the critical value.

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Q10: In a certain school district, a survey of 200 students showed that 32% carried lunches to school. Find the 95% confidence interval of the true proportion of students who carry their lunches to school. Express the interval as a percent rounded to one decimal place.

Q8: Find the 95% confidence intervals for the variance of the weights of 42 one-gallon containers of motor oil if a sample of 21 has a variance of 6.3. The weights are given in ounces. Assume the variable in normally distributed. Round your calculations to one decimal place.
Q7: A study indicated that 38% of children ages 2-5yrs old 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 4% with 95% confidence. A sample size of _______ children is needed.

Q6: A medical researcher wishes to determine the percentage of females who takes vitamins. He wishes to be 99% confident that the estimate is 4% of the true proportion. A recent study of 295 females showed that 35% took vitamins. How large should the sample size be? _______ females

Q5: Nine women had an average heart rate of 114 beats per minute. The standard deviation of the sample was 6 beats. Find the 99% confidence interval of the true mean for the women.
Q9: The average yearly cost per household of owning a dog is \$214.28. Suppose that we randomly select 30 households that own a dog. What is the probability that the sample mean for these 30 households is less than \$222.00? Assume α = \$28. Round your answer two decimal places.