Showing 1–16 of 42 results

Sale!
A true/false test has 90 questions. A passing grade is 59% or more correct answers. Find the approximate probability that a person who is just guessing will pass the test.
$2.00$1.00Question: A true/false test has 90 questions. A passing grade is 59% or more correct answers. Find the approximate probability that a person who is just guessing will pass the test.

Sale!
A study is conducted to determine if a newly designed text book is more helpful to learning the material than the old edition. the mean score
$5.00$3.00Question: a study is conducted to determine if a newly designed text book is more helpful to learning the material than the old edition. the mean score on the final exam for a course using the old edition is 75. ten randomly selected people who used the new text take the final exam their scores are shown.
person: A,B,C,D,E,F,G,H,I,J
score: 90,74,96,95,89,71,80,86,67,78
Use a 0.01significance level to test the claim that people do better with the new edition. Assume the standard deviation is 10.5. ( Note you may wish to use statistical software).
A.)what kind of test should be used?
1. twosided tail
2. one tailed
3. it does not matter
B.) the test statistic is (rounded to two decimals)
C.) the Pvalue is
D.) is there sufficient evidence to support the claim that people do better than 75 on this exam? Y/N
E.) construct a 99% confidence interval for the mean score for students using the new text. ____<mean<____ 
Sale!
Calculated Numeric: A survey of an introductory statistics class in Fall 2003 asked students
$3.00$2.00Quesiton: Calculated Numeric: A survey of an introductory statistics class in Fall 2003 asked students whether or not they ate breakfast the morning of the survey. Results are as follows:
Breakfast Yes No Gender Male 66 66 Female 125 74 What is the probability that a randomly selected student is female? Round to three decimals.

Sale!
A study of the ability of individuals to walk in a straight line (” Can we Really walk straight?” Amer. J. of Physical Anthro., 1992: 1927)
$3.00$2.00 
Sale!
For a population of N = 4 scores with SX = 10 and SX2 = 30, SS = 5. A.True B.False
$2.00$1.00For a population of N = 4 scores with SX = 10 and SX^{2} = 30, SS = 5.
A.True
B.False

Sale!
G and H are mutually exclusive events. P(G)=0.5 P(H)=0.3. a. Explain
$3.00$2.00Question: G and H are mutually exclusive events. P(G)=0.5 P(H)=0.3. a. Explain why the following statement MUST be false: P(HG)=0.4. b. Find P(H OR G). c. Are G and H independent or dependent events? Explain in a complete sentence.

Sale!
Student A is absent 20% of the time and student B is absent 30% of the time. What is the
$3.00$2.00Question: Student A is absent 20% of the time and student B is absent 30% of the time. What is the probability that exactly one of them absent today?

Sale!
You generate a 95% confidence interval for the mean carapace width of dungeness crabs, which is
$3.00$2.00Question:
You generate a 95% confidence interval for the mean carapace width of dungeness crabs, which is 141 +/18 millimeters. Which answer below could you use to improve your estimate (i.e. make your margin of error smaller)?
 Increase the confidence level to 99%.
 Invoke the Central Limit Theorem.
 Increase the number of crabs in your sample
 Eat one out of every 10 crabs in your sample so that you don’t get hungry while you’re making measurements..

Sale!
An opinion poll asks a simple random sample of 200 United States immigrants how they view their job prospects. In all, 121 say “good.” Does the poll give
$4.00$3.00An opinion poll asks a simple random sample of 200 United States immigrants how they view their job prospects. In all, 121 say “good.” Does the poll give convincing evidence to conclude that more than half of all immigrants think their job prospects are good? If P “the proportion of all immigrants who say their job prospects are good, what are the hypotheses for a test to answer this question.

Sale!
Assume that airplanes land independently of one another on a particular runway. If there is an 8% chance that no airplanes land in an hour, what is the probability that six airplanes land in an hour?
$3.00$2.00Question: Assume that airplanes land independently of one another on a particular runway. If there is an 8% chance that no airplanes land in an hour, what is the probability that six airplanes land in an hour?
A: 0.6188
B: 0.7351
C: 0.1515
D: 0.0288

Sale!
A manufacturer knows that their items have a normally distributed lifespan, with a mean of 7 years, and standard deviation of 1.6 years.
$3.00$2.00Question: A manufacturer knows that their items have a normally distributed lifespan, with a mean of 7 years, and standard deviation of 1.6 years.
If you randomly purchase one item, what is the probability it will last longer than 11 years?

Sale!
Given set A contains the elements (a, b, c, d, e, f) and set B contains the elements (e, f, g, h, i, j) in a world where elements (a, through n) exist
$3.00$2.00Given set A contains the elements (a, b, c, d, e, f) and set B contains the elements (e, f, g, h, i, j) in a world where elements (a, through n) exist as shown in the diagram below
what are the elements of: ?
Select one:
 Elements (a, b, c, d, g, h, i, j)
 Elements (a, b, c, d, k, I, m, n)
 Elements (e, f, k, I, m, n)
 Elements (e. f, g, t, i,j)

Sale!
In the Health ABC Study, 547 subjects owned a pet and 1971 subjects did not. Among the pet owners, there were 300 women
$5.00$4.00Question: In the Health ABC Study, 547 subjects owned a pet and 1971 subjects did not. Among the pet owners, there were 300 women; 982 of the nonpet owners were women. Find the proportion of pet owners who were women. Do the same for the nonpet owners. (Be sure to let Population 1 correspond to the group with the higher proportion so that the difference will be positive. Round your answers to three decimal places.)
Give a 95% confidence interval for the difference in the two proportions. (Do not use rounded values. Round your final answers to three decimal places.)

Sale!
A machine that fills cans of Mountain Lightning is supposed to put 12 ounces of beverage in each can. The variance of the amount in each can is 0.01.
$2.00$1.00Question: A machine that fills cans of Mountain Lightning is supposed to put 12 ounces of beverage in each can. The variance of the amount in each can is 0.01. The machine is moved to a new location, which has previously been shown to alter the machine settings. Determine whether the variance has changed following the move based on the following sample of the fills of 10 Mountain Lightning cans.
12.18 11.77 12.09 12.03 11.87 11.96 12.03 12.36 12.28 11.85 
Sale!
A tire manufacturer produces tires that are believed to have a mean life of at least 25,000 miles when
$4.00$3.00Question: A tire manufacturer produces tires that are believed to have a mean life of at least 25,000 miles when the production process is working correctly. Based on past experience, the population standard deviation of the lifetime of the tires is 3,500 miles. Assume a level of significance for testing of 5%, and a random sample of 100 tires:
A) What would be the consequences of making a Type II error in this problem?
B) Compute the Probability of making a Type II error if the true population mean is 24,000 miles 
Sale!
Ben is interested in flirting. He wants to know what kinds of people
$10.00$8.00Question: Ben is interested in flirting. He wants to know what kinds of people are likely to be good (and bad) at flirting. He thinks that selfconfidence will be correlated with flirting ability, but he’s not sure which way it will go. High selfconfidence should make for good flirters, but if people are too selfconfident, it might hurt their flirting performance. So he gives a number of students a selfconfidence measure (Y) and then watches them try to flirt with people at an offcampus bar (X). Both scales range from 1 (low) to 7 (high). He records the following scores:
SelfConfidence (X) Flirting (Y) 4 5 6 3 6 5 7 6 6 7 3 1 6 4 2 3 3 2 3 4  a) Compute the correlation for these scores. (SHOW YOUR WORK! Use as much space as necessary.)
 b) What does this correlation tell us about the relationship between selfconfidence and flirting ability?
 c) What is Ben’s alternative hypothesis?
 d) What is Ben’s null hypothesis?
 e) What is the coefficient of determination for these scores?
 f) How did you compute the coefficient of determination?
 g) How many degrees of freedom are there in this example?
 h) How did you compute the degrees of freedom? Should Ben perform a onetailed or twotailed test? Why?
 i) Assuming α = .05, what is the critical value for this example?
 j) Is the correlation you computed statistically significant? YES or NO
 k) How do you know whether or not the correlation is statistically significant?