Statistics and Probability Answers

suppose that you own 8 math books and 6 computer science books and wish to fill 7 position on a shelf. what is the probability that the first 4 position are to be occupied by math books and the last 3 by computer science books?

Unisys.com is one of the most frequented business to business web sites. according to a wall street journal article, business partners accessing Unisys.com spend an average of 65.7 minutes, possibly the longest average time per visit of any business to business website. assuming that the duration of a visit to this website is normally distributed with mean of 65.7 minutes and the standard deviation of 15 minutes. (A) what is the probability that the randomly selected visit will last between 60 and 90 minutes. (B) between what values, symmetrically distributed around the mean will90% of visit last?

Nancy is throwing a standard six sided die. If she throws a 4 on her first throw, what is the probability that her next throw will NOT be. A 4?

The student body at St. Algebra College attends an average of 3.3 parties per month. A random sample of 117 sociology majors averages 3.8 parties per month, with a standard deviation of 0.53. Are sociology majors significantly different from the student body as a whole?

a matchbox is dropped on the table.
experiments show that it lands:on its end with probability 0.1
on its edge with probability
and the rest of the time with its flat face.
what is the probability that the first box lands on its end and the second box land on its flat face

a matchbox is dropped on the table.
experiments show that it lands:on its end with probability 0.1
on its edge with probability
and the rest of the time with its flat face.
what is the probability that both boxes land on their edges?

For the following listed, the x value is first, the px is second... 0, .236, 1, .396, 2, .264, 3, .088, 4, .015, 5, .001. Need to find the mean, expected number, and standard deviation.

A business man has 2 independent investment A and B available to him, but he llacks the capital to undertake both of them simultaneously. He can choose to take A first and then stop, of if A is unsucsessful then take B or vice versa. The probability of success on A is 0.7 while for B it is 0.4. Both investments rquire an initial capital outlay of R2000 and both return nothing if the venture is unsucessful. Sucessful completion of A will return R3000 (over cost), while sucessful completion of B will return R5000 (over cost)

How would I prepare a report with the aid of a decision tree, advising the investor of the best course of action?

normal-shaped distribution has μ = 80 and σ = 15.
a. sketch the distribution of sample means for samples of n = 25 scores from this
population
b. what are the z-score values that form the boundaries for the middle 95% of the distribution of the sample means?
c. compute the z-scores for M = 89 for a sample of n = 25 scores. Is this sample mean in the middle 95% of the distribution? Is this sample mean in the middle 99% of the distribution?
d. compute the z-score for M = 84 for a sample of n = 25 scores. Is this sample mean in the middle 95% of the distribution?

1. Compute each value requested for the following set of scores.

X

0 ΣX + 10

6 Σ(X + 10)

2 Σ(X + 1)2

3 Σ(X – 1)2 + 5

(X - X )2


2. For each of the following cases, name the observed variable and then classify (with expla- nation) the type and nature (discrete or continuous) of the scale:

a) Several respondents were interviewed and asked a few questions. For each question, their responses were coded as Strongly Agree, Strongly Disagree and No Comment.

b) A researcher is investigating the estimated time taken by students to complete an as- signment.

c) A poll studying the number of readers of three leading national news paper; Berita Ha- rian, Utusan Malaysia and New Straits Times.

d) A researcher is studying individual perception of his/her own self-esteem using a 10- point scale self-perception battery.

e) A teacher is grading her students’ academic performance into three different catego- ries: Low Achievers, Average Achievers and High Achievers