MATH 1530 – Quiz # 7



MATH 1530 – Quiz # 11 (Quizpak 5) Name _____________________________

Assume that the readings on thermometers are normally distributed with a mean of [pic] and a standard deviation of [pic]. One thermometer is randomly selected and tested. In each case, label and shade the graph , then find the probability of getting the stated readings in degrees Celsius. Show the areas to be added or subtracted as read from Table A-2 as well as the solution.

1. Between [pic] and [pic]

[pic] = ___________________________ = ______________

2. Between [pic] and [pic]

[pic] = ___________________________ = ______________

3. Less than [pic]

[pic] = ___________________________ = ______________

4. Greater than [pic]

[pic] = ___________________________ = ______________

MATH 1530 – Quiz # 12 (Quizpak 5) Name _____________________________

Find the missing “z-value” given each of the following probabilities come from a Standard Normal Distribution. In each case, label and shade the graph writing the appropriate probabilities over the shaded region, then state the z-score that provides those probabilities as your solution.

1. If [pic], then [pic]= _____________ .

2. If [pic], then [pic]= _____________ .

3. If [pic], then [pic]= _____________

and [pic] = _____________ .

4. If [pic], then [pic]= _____________ .

MATH 1530 – Quiz # 13 (Quizpak 5) Name _____________________________

Let [pic] be a randomly selected score from a normally distributed population with mean [pic] and standard deviation [pic], then find each of the following probabilities. Label and shade the graphs accordingly. Show the areas to be added or subtracted as read from Table A-2 as well as the solution.

1.

[pic] = [pic] = ___________________ = __________

2.

[pic] = [pic] = ________________________ = ______________

3.

[pic] = [pic] = ________________________ = ______________

4.

[pic] = [pic] = _____________________ = __________

MATH 1530 – Quiz # 14 (Quizpak 5) Name _____________________________

Given a normally distributed population with mean [pic] and standard deviation [pic], find each of the following scores. Label the graphs accordingly. Show formulas and calculations below the graphs.

1. The score that separates the top 40% from the bottom 60%. ______________

2. The score that separates the bottom 10% from the top 90%. ______________

3. The score that separates the top 10% from the bottom 90%. ______________

4. The score that determines the cut-off for the top 25%. ______________

MATH 1530 – Quiz # 15 (Quizpak 5) Name _____________________________

Assume that women’s heights are normally distributed with a mean of [pic] inches and a standard deviation [pic] inches (based on data from the National Health Survey).

1. If 1 woman is selected at random, find the probability that her height is above 63 inches.

P( ) = P( ) = ________________________ = _______________

2. If 100 women are selected at random, find the probability that their mean height is greater than 63 inches.

P( ) = P( ) = ________________________ = _______________

3. Consider the sampling distribution of randomly selecting 100 women at a time and recording the mean heights, then this distribution of sample means has a mean and a standard deviation that are equal to:

(give the numerical values here) [pic] = _______________

[pic] = _______________

MTH 1050 – STATDISK WORKSHEET - CHAPTER 5 Name _______________________

1. a. Use STATDISK to generate 106 values from a normally distributed population with a mean of 98.6 and a standard deviation of 0.62. Use Data/Descriptive Statistics to find the mean of the generated sample.

b. Record the 10 sample means here: (Use decimals = 1 and seed = 1, 2, … , 10)

_____ _____ _____ _____ _____ _____ _____ _____ _____ _____

c. After examining those 10 sample means, what do you conclude about the likelihood of getting a sample mean of 98.20? Explain.

_______________________________________________________________________________

_______________________________________________________________________________

d. Given that researchers did obtain a sample of 106 temperatures with a mean of 98.20[pic]F, what does their result suggest about the common belief that the population mean is 98.6[pic]F?

_______________________________________________________________________________

5-2 a. Sample mean: __________ Standard deviation: __________

b. Record the 10 sample means here. (Use decimals = 2 and seed = 1, 2, … , 10)

_____ _____ _____ _____ _____ _____ _____ _____ _____ _____

5-3 a. P( ) = _____________________________ = _____________________

b. P( ) = _____________________________ = _____________________

c. P( ) = _____________________________ = _____________________

d. P( ) = _____________________________ = _____________________

e. P( ) = _____________________________ = _____________________

5-5 a. One Die: Mean: __________

(seed = 5) Standard Deviation: __________

Distribution shape: _______________________________

Sketch histogram here.

b. Two Dice: Mean: __________

(seed = 5) Standard Deviation: __________

Distribution shape: _______________________________

Sketch histogram here.

c. 10 Dice: Mean: __________

(seed = 5) Standard Deviation: __________

Distribution shape: _______________________________

Sketch histogram here.

d. 20 Dice: Mean: __________

(seed = 5) Standard Deviation: __________

Distribution shape: _______________________________

Sketch histogram here.

e. General conclusions:

What happens to the mean as the sample size increases from 1to 2 to 10 to 20?

_______________________________________________________________________________

What happens to the standard deviation as the sample size increases?

_______________________________________________________________________________

What happens to the distribution shape as the sample size increases?

_______________________________________________________________________________

How do these results illustrate the central limit theorem?

_______________________________________________________________________________

_______________________________________________________________________________

The following notes will be provided for your reference as the last page of Exam 3:

The Standard Normal Distribution is a normal probability distribution that has a mean of [pic] and a standard deviation of [pic]. (Utilize Table A-2 to find probabilities for given z-scores or to find z-scores for given probabilities.)

Formula for converting x-scores to z-scores:

[pic]

Formula for converting z-scores to x-scores:

[pic]

The Central Limit Thereom:

For large sample sizes (n>30) drawn from ANY distribution (or for smaller sample sizes, if the original distribution is normally distributed), the sampling distribution of the means has the following properties:

1. The distribution of the sample means is approximately Normal.

2. The mean of the sampling distribution is equal to the mean of the population.

[pic]

3. The standard deviation of the sampling distribution is equal to the standard deviation of the population divide by the square root of n.

[pic]

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[pic]

0 z

[pic]

0 z

[pic]

100 x

[pic]

0 z

[pic]

100 x

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

100 x

[pic]

100 x

[pic]

100 x

[pic]

0 z

[pic]

0 z

[pic]

0 z

[pic]

100 x

[pic]

0 z

[pic]

100 x

[pic]

0 z

[pic]

100 x

[pic]

[pic]

[pic]

[pic]

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