In forest, the average number of maples was 20 trees/plot with a standard deviation of 7...

In forest, the average number of maples was 20 trees/plot with a standard deviation of 7 trees/plot. If we take a sample of eight plots, what is the probability that the mean of this sample will be between 18 and 21?

Assuming the octane ratings are normally distributed, use the octane ratings data to construct a 95% confidence interval for the mean octane rating.

We want to test how accurate an optical character recognition (OCR) device is. We collect a sample of 500 handwritten words and find out that 440 were read correctly. Construct a 95% confidence interval for the population proportion.

We want to see what proportion of seeds will germinate. We plant 200 seeds and see that 194 germinate. Construct a 95% confidence interval for the population proportion.

Expert Solution

Solution:

a)

b)

c)

d)

orchestra answered 2 years ago

Suppose that 20% of the trees in a forest are infested with a certain type of...

Suppose that 20% of the trees in a forest are infested with a certain type of parasite. (a) What is the probability that in a random sample of 300 trees, between 18% and 21% of the trees will have the parasite? . Include in your answer the proper check to confirm that you should be using the normal table to help answer this question. (b) You sample 300 trees, and find that 78 trees have the parasite. Based on this,...

The average number of words in a romance novel is 64,393 and the standard deviation is...

The average number of words in a romance novel is 64,393 and the standard deviation is 17,382. Assume the distribution is normal. Let X be the number of words in a randomly selected romance novel. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N(_,_) b. Find the proportion of all novels that are between 52,226 and 62,655 words. c. The 70th percentile for novels is words. (Round to the nearest word)...

The average number of words in a romance novel is 64,245 and the standard deviation is...

The average number of words in a romance novel is 64,245 and the standard deviation is 17,316. Assume the distribution is normal. Let X be the number of words in a randomly selected romance novel. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N( , ) b. Find the proportion of all novels that are between 48,661 and 65,977 words. c. The 95th percentile for novels is words. (Round to...

The average number of words in a romance novel is 64,200 and the standard deviation is...

The average number of words in a romance novel is 64,200 and the standard deviation is 17,431. Assume the distribution is normal. Let X be the number of words in a randomly selected romance novel. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N( , ) b. Find the proportion of all novels that are between 62,457 and 74,659 words. c. The 95th percentile for novels is words. (Round to...

The average number of words in a romance novel is 64,419 and the standard deviation is...

The average number of words in a romance novel is 64,419 and the standard deviation is 17,160. Assume the distribution is normal. Let X be the number of words in a randomly selected romance novel. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N(,) b. Find the proportion of all novels that are between 71,283 and 83,295 words. c. The 85th percentile for novels is words. (Round to the nearest word)...

The average number of words in a romance novel is 64,290 and the standard deviation is...

The average number of words in a romance novel is 64,290 and the standard deviation is 17,422. Assume the distribution is normal. Let X be the number of words in a randomly selected romance novel. Round all answers to 4 decimal places where possible. a. What is the distribution of X? X ~ N(___,____) b. Find the proportion of all novels that are between 57,321 and 71,259 words. _____ c. The 95th percentile for novels is ____ words. (Round to...

The average number of sales at a car dealership is 24 with a standard deviation of...

The average number of sales at a car dealership is 24 with a standard deviation of 5. A week ago, you were promoted to manager. Over this week (seven days), the average number of sales has dipped to 20. Your boss says he is coming by tomorrow to check out how you have been doing. You know that your boss has a rule where he will fire any manager if the average number of sales is statistically lower than 24...

7(B) The weight of an average footballer in team A is 220lbs. The standard deviation is...

7(B) The weight of an average footballer in team A is 220lbs. The standard deviation is 15lbs. A coach scouting a sample of 4 footballers will sign them if the sample mean weight is less than 215lbs. What is the probability that he will sign them? If the coach samples 100 players, what is the probability that the sample mean weight will be less than 215?

The average price of a college math textbook is $171 and the standard deviation is $20....

The average price of a college math textbook is $171 and the standard deviation is $20. Suppose that 17 textbooks are randomly chosen. Round all answers to 4 decimal places where possible. A. What is the distribution of ¯x? ¯x ~ N( , ) B. For the group of 17, find the probability that the average price is between $172 and $176. C. Find the third quartile for the average textbook price for this sample size. $ (round to the...

The average annual rainfall in City A is 20 inches, with a standard deviation of 3...

The average annual rainfall in City A is 20 inches, with a standard deviation of 3 inches. The annual rainfall in City B is 45 inches, with a standard deviation of 12 inches. In a given year, City A received 25 inches, while City B received 55 inches. Assuming both rainfall distributions are approximately normal, which city had the wettest year relative to its average distribution? a.City A b.City B c.The cities had equally wet years d.Cannot tell from the...

Question