Statistics Homework Help

Posted on 2013-11-26 16:25:00 in Statistics by DANGEROUS

I have no idea what I am doing for my stats homework please help and if it is not too much trouble can you explain it?



The average satellite TV bill in Oil City for a random sample of 24 households is $50 with a sample standard deviation of $14. Determine the 80% confidence interval for this sample. What is the lower confidence level? Round to the nearest 2 decimal points.



Your Answer:





The Red Lobster bill for a random sample of 21 eatters at a local restaurant is $110 with a sample standard deviation of $25. Determine the 95% confidence interval for this sample. What is the upper confidence level? Round to the nearest 2 decimal places.



Your Answer:



Random sample of 29 college students who averaged 7.5 hours of school work per night. Assume the population standard deviation is 2.5 hours. Calculate a 98% confidence interval for the mean. Enter the upper confidence level for this interval. Round to the nearest two decimal places.



Your Answer:



The proportion of homeless cats in the Pennsylvania western region is to be estimated to within ± 0.002, with a confidence level of ninety five percent. If the proportion is thought to be around 0.19, what sample size should be used? Round your answer to the next whole number (that means round 0.5 to 1, or 2.1 to 2).



Your Answer:



The Central Limit Theorem states that as sample size increases, the population distribution more closely approximates a normal distribution.

True

False



If a population is known to be normally distributed, then it follows that the sample standard deviation must equal ?.

options:

True

False



In order to select a stratified random sample, we divide the population into overlapping groups of similar elements.

options:

True

False



Consider a sampling distribution formed based on n = 3. The standard deviation of the population of all sample means ?x? is ______________ less than the standard deviation of the population of individual measurements ?.



Question 9 options:

A)

Sometimes



B)

Always



C)

Never



According to the Central Limit Theorem, if a sample size is at least _____, then for most sampled populations, we can conclude that the sample means are approximately normal.



options:

A)

30



B)

1000



C)

50



D)

100





Assume that the systolic blood pressure of 25-year-old females is normally distributed, with an average of 142 mmHg and a standard deviation of 43 mmHg.-------- A random sample of 80 men from this age group is selected. To calculate the probability that the average blood pressure of the sample will be greater than 145 mmHg, we would need a Z score. What is that Z value? ------- Round your answer to the nearest 2 decimal points. (If it is negative, remember to put in the minus sign).



Your Answer:





Assume that the systolic blood pressure of 40-year-old males is normally distributed, with an average of 122 mmHg and a standard deviation of 10 mmHg. A random sample of 16 men from this age group is selected. Calculate the probability that the average blood pressure of the sample will be greater than 125mmHg. ------- Round your answer to the nearest 2 decimal points. (If it is negative, remember to put in the minus sign).



options:

A)

0.1151



B)

0.4750



C)

0.7555



D)

0.2333





The number of defectives in 5 different samples of 100 observations each is the following: 36,15,34,43, and 39. What is the estimate of the population proportion of defectives? ------- Round your answer to the nearest 3 decimal points.

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