please help

Jlo · 2011-05-18 00:06:35

i have a few questions for you, could you help me.

1. a) for the following data set, calculate the mean, median, mode: 14, 18, -10, 8,8, -16

b) find the range and a standard deviation for the data: 17, 18, 19, 20, 21, 22, 23

2. a) a restaurant menu has four kinds of soups, eight kinds of main courses, five kinds of deserts and six kinds of drinks. If a customer randomly selects one item from each of these four categories, how many different outcomes are possible?

b) of 12 possible books, you plan to take 4 with you on vacation. How many different collections of four books can you take?

3. How many distinct permutations can be formed using the letters of the word CINCINNATI?

4. The probability that randomly selected school teacher is a female is 0.68, holds a second job is 0.38 and is a female and holds a second job is 0.29. Find the probability that a randomly selected school teacher is a female or holds a second job.

5. The following table gives the probability distribution of a discrete random variable x

------------------------------------------------
x | 0 | 1 | 2 | 3 | 4 | 5
------------------------------------------------
P(x) | 0.03 | 0.17 | 0.22 | 0.31 | 0.15| 0.12
------------------------------------------------

Find the follwing probabilities:

a) P(x=1); b) P(x < _ 1); c) P(x >_ 3); d) P(0 _< x _< 2); Probability that x assumes a value less than 3.

6. a) If x is a binomial random variable, calculate the probability of x, find the mean and standard deviation for n=8, x=5, p=70.

b) Spoke Weaving Corporation has eight weaving machines of the same kind and of the same age. The probability is 0.04 that any weaving machine will break down at any time. Find the probability that any given time: 1) exactly two weaving machines will be broken down; 2) none of the weaving machines will be broken down.

7. a) A set of data items is normally distributed with a mean of 50. Convert the data item x=30 to a z-score, if the standard deviation is 8.

b) According to the survey, married men aged 25 to 54 who work full time sleep average of 7.43 hours per night. Assume that currently the times that such a men sleep per night have a normal distribution with a mean of 7.43 hours an a standard deviation of 0.80 hours. Find the percentage of such a men who sleep 1 between 6.5 and 8.5 hours 2) less than 6 hours.

8. a) A set of data items is normally distributed with a mean of 200. Find the data item in this distribution that corresponds to the z-score of -2, if the standard deviation is 25.

b) It is known that the life of a calculator manufactured by Texas Instruments has a normal distribution with a mean of 54 months and a standard deviation of 8 months. What should the warranty period be to replace a malfunctioning calculator if the company does not want to replace more than 1% of all calculators sold?

9. a) Use the sample data and confidence level to find the margin of error E and to construct the confidence interval estimate of the population proportion p: n=1068, x=267, 95% confidence.

b) Use given margin of error, confidence level, and population standard deviation Q to find the minimum sample size required to estimate an unknown population mean y.
Margin of error: $1; confidence level: 95%; Q = $12.

10. Use the following data a) determine coefficient of correlation, rounded to the nearest thousandth, b) find the equation of the regression line for time watching TV and time on the internet,
c)approximate how much time on the internet can we predict for a person who spends 10 hours weekly watching TV

--------------------------------------------------------
Subject A | B | C | D | E | F | G
--------------------------------------------------------
Time watching TV 7 | 3 | 1 | 6 | 6 | 4 | 5
--------------------------------------------------------
time on internet 11 | 9 | 5 | 14 | 15 | 6 | 15
--------------------------------------------------------

bobbym · 2011-05-18 00:14:09

Hi;

1a)

The mean is:

The median is 8. The mode is 8.

Please go here.

http://www.mathsisfun.com/median.html

http://www.mathsisfun.com/mode.html

2) 4 x 8 x 5 x 6 = 960

3)

3. How many distinct permutations can be formed using the letters of the word CINCINNATI?

There are 10 letters, 2C's, 3 I's, 3 N's, 1 A and 1 T.

Now I have started you off with the first three because you are new here. Please show what work you have done on the rest. Any work. Something to show me what you understand and what you do not.

There are some interesting problems in there. I would be glad to work on them with you but it is wrong to just get answers. Statistics is a nice field let's work on them together.

Bob · 2011-05-18 00:50:09

hi bobbym,

How are you today?

Bob

bobbym · 2011-05-18 00:57:00

Hi Bob;

Not bad, how are you?

Bob · 2011-05-18 01:08:16

hi bobbym,

I'm glad to hear that. I'm fine. Just about to go out in the garden to be given my orders by 'the boss'.

Still no rain here in Essex. Do you know any good (Navaho) rain chants?

Bob

Math Is Fun Forum

#1 2011-05-18 00:06:35

please help

#2 2011-05-18 00:14:09

Re: please help

#3 2011-05-18 00:50:09

Re: please help

#4 2011-05-18 00:57:00

Re: please help

#5 2011-05-18 01:08:16

Re: please help

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