Question

1. If a population does not have a normal distribution, the shape of the corresponding x-bar curve will be

   	a.	exactly normal
   	b.	approximately normal
   	c.	Non-normal
   	d.	depends on the sample size

1 points   

QUESTION 2

1. Ch7 Terms 5:
   
   As sample size increases, the standard deviation of the x-bar curve will

   	a.	increase
   	b.	decrease
   	c.	remain unchanged
   	d.	explode

1 points   

QUESTION 3

1. Ch7 Terms 11 TF:
   
   As sample size increases, the distribution of an xbar curves becomes more and more normal in shape.

   	a.	TRUE
   	b.	FALSE

1 points   

QUESTION 4

1. 17 term 5:
   
   A sample average is useful because it is identical to the population average

   	a.	TRUE
   	b.	FALSE

1 points   

QUESTION 5

1. AInv Prob percentiles 6:
   
   Use your TI83 (or Excel):
   
   A normally distributed population has a mean of 93 and a standard deviation of 12. Determine the value of the sample average at the 75th percentile for samples of siz 43.
   
   Round to the nearest tenth

2 points   

QUESTION 6

1. sigma xbar 1:
   
   Suppose a sample of 77 healthy adult human body temperatures is taken from a population with a standard deviation of 0.3 degrees Fahrenheit. What would be the sampling deviation of the sample mean?
   
   Round to the nearest thousandth

2 points   

QUESTION 7

1. Prob 6 11B:
   
   Use your TI83 (or Excel):
   
   A certain giant tortoise has a life span that is normally distributed with a mean age of 72 years and a standard deviation of 19 years. Determine the probability that a random sample of 37 such tortoises has an average life span between 70 and 81 years.
   
   Round to four decimal places.

2 points   

QUESTION 8

1. Prob 1 11B:
   
   Use your TI83 (or Excel):
   
   A Test has scores that are normally distributed with a mean of 79 and a standard deviation of 14. Determine the probability that a random sample of 31 test scores has an average greater than 77.
   
   Round to four decimal places.

2 points   

QUESTION 9

1. interval 5:
   
   A normally distributed population has a mean of 90 and a standard deviation of 19. Sample avergaes from samples of size 13 are collected. What would be the upper end of the centered interval that contains 95% of all possible sample averages?
   
   Round to the nearest hundredth

2 points   

QUESTION 10

1. Dinner app 1 ch 11B:
   
   Use your TI83:
   
   At a certain restaurant in Chicago, the average time it takes a person to eat a nice dinner is 55 minutes with a standard deviation of 20 minutes. These times are known to be normally distributed.
   
   To Four decimal places, what is the probability a random diner will finish dinner in more than 54 minutes?

Answer 1

dear student we can provide you with 4 Multiple choice question at a time. Please post the question one at a time or accordingly.

According to the Central limit theorem that states that if a large enough sample is taken even from a not normal ddistribution (typically n > 30) then the sampling distribution of is approximately a normal distribution with a mean of and a standard deviation of .

1) hence the right answer is option d

2) the standard deviation of the is if the population standard deviation is not given is

option B is right . As the sample size increases, the standard deviation decreases.

3) according to the central limit theorem above statement is true.

4) Sample average is the point estimate for the population mean.

If the sample is a simple random sample, the sample mean is an unbiased estimate of the population mean

hence option A is right