1 is an example of a sample statistic population parameter p

1- is an example of a:

sample statistic

population parameter

population variance

mode

none of the above answers is correct

2- A continuous random variable may assume

Question:

all the positive integer values in an interval

only integer values in an interval or collection of intervals

only fractional values in an interval or collection of intervals

all values in an interval or collection of intervals

3- Larger values of the standard deviation result in a normal curve that is:

narrower and more peaked

shifted to the left

shifted to the right

wider and flatter

4- A negative value of Z indicates that:

the number of standard deviations of an observation is to the left of the mean

the number of standard deviations of an observation is to the right of the mean

a mistake has been made in computations, since Z cannot be negative

the data has a negative mean

5- Since the population size is always larger than the sample size, then the sample statistic

can never be larger than the population parameter

can never be equal to the population parameter

can never be zero

can never be smaller than the population parameter

none of the above answers is correct

6- The monthly income of residents of Daisy City is normally distributed with a mean of $3000 and a standard deviation of $500. (please show some work even if you use a computer!)

a. The mayor of Daisy City makes $2,250 a month. What percentage of Daisy City\'s residents has incomes that are more than the mayor\'s?

b. Individuals with incomes of less than $1,985 per month are exempt from city taxes. What percentage of residents is exempt from city taxes?

c. Two hundred residents have incomes of at least $4,440 per month. What is the population of Daisy City?

	sample statistic
	population parameter
	population variance
	mode
	none of the above answers is correct

Solution

1) 1- is an example of a: population parameter ( MU is used for population mean and hence parameter)

2) 2- A continuous random variable may assume --all values in an interval or collection of intervals

(Example (0,1) means all real values between 0 and 1)

3) 3- Larger values of the standard deviation result in a normal curve that is:Wider and flatter

4- A negative value of Z indicates that:the number of standard deviations of an observation is to the left of the mean

(Std normal curve is symmetrical about mean)

5. Since the population size is always larger than the sample size, then the sample statistic

none of the above answers is correct

6) X- monthly income is Normal (3000,500)

Z = (x-3000)/500

Mayor z value = -750/500 = -1.5

P(Z>-1.5) =0.9332

Hence 93.32% earn more than mayor

b) X<1985 are exmpt

Z<-1015/500 = -2.03

P(Z<-2.03) = 0.0212

Hence 2.12% people are exempt from IT
-------------------------------

c) X>=4440 means Z>=1440/500 = 2.88

Prob = 0.5-0.4979=0.0021

If 0.0021 correspond to 200

total population 1 = 200/0.0021 = 952.38

= 952