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Question

Question 6
 

  
 
Which of the following is NOT TRUE concerning the graphic depiction ("the curve") of a distribution for means?

Question options:

 
A) 
The curve is skewed to the right. 
 
B) 
The area under the curve is one.
 
C) 
The mean, median, and mode are equal.
 
D) 
The curve never touches the x-axis.

 

 

Question 8
 
 
 
According to the WHO MONICA Project the mean systolic blood pressure for people in China is 128 mmHg with a standard deviation of 23 mmHg (Kuulasmaa, Hense & Tolonen, 1998).  Systolic blood pressure is normally distributed.

a.)    TRUE or FALSE:  The random variable is defined as systolic blood pressure of a person in China.

b.)    For a sample of size 15, state the mean of the sample mean.

c.)    For a sample of size 15, state the standard deviation of the sample mean (the "standard error of the mean").

d.)    Suppose a sample of size 15 is taken.  Find the probability that the sample mean systolic blood pressure is more than 135 mmHg.

For part (a):  Enter TRUE or FALSE

For parts (b) through (d), enter answer in decimal form rounded to nearest thousandth (3 places after decimal).  Examples of correctly entered answers: 0.000   0.004   0.080   1.200    0.594    13.000

#1

#2

#3

#4

Answer 1

#6 - the distribution of means will also be a normal distribution, so it won't be skewed.

 

#8 a) true

b) You would expect the mean of the sample mean to be the same as the population mean, x = 128

c) The SD of the sample mean is found with the formula

 

σ_x = ^σ/√n

 

d) Calculate the Z score using Z = (x-μ)/_(σ/√n)

Find the probability matching the Z score, P

Since you want the probability greater than, you take 1 - P

 

Or use your calculator and a normalcdf function