Subject Mathematics Advanced Statistics

Question

4)
On a physical fitness test middle school boys are awarded one point for each push-up they can do, and a point for each sit-up. National results show that the expected value is 18 pushups with a standard deviation of 4 push-ups, and an expected value of 34 sit-ups with standard deviation 11 sit-ups. The expected value of their combined (total) scores is therefore 18 + 34 = 52 points. If the number of push-ups and the number of sit-ups are independent, what is the standard deviation of their combined scores?
A) 11.7 B) 15 C) 5.3 D) 7.2 E) 137

14)
One of the leading dot-com companies has found that the proportion of customers who come into its web site that actually makes a purchase is 0.045. After changing the design of the web site the company checks whether the 0.045 purchase rate still holds by selecting a random sample of 200 hits on their Web site. Given that the 0.045 rate still applies, what is the standard deviation of the sampling distribution of the sample proportion?
A) About 0.0002 B) About 0.0354 C) Approximately 0.0147 D) Can't be determined since the shape of the population distribution is not known.

16)
A printing company guarantees that no more than 5% of pages that it prints for textbooks have any type of printing error. Suppose that the printing company selects a random sample of 400 recently printed pages and finds 33 (8.25%) that have an error. If the printer is meeting the 5% standard, what is the probability that 8.25% or more of the pages in a sample of 400 pages would have errors ?
A) 0.1245 B) 0.4986 C) 0.0014 D) 0.1250

24)
A physical fitness association is including the mile run in its secondary-school fitness test. The time for this event for boys in secondary school is known to possess a normal distribution with a mean of 450 seconds and a standard deviation of 40 seconds. The fitness association wants to recognize the fastest 10% of the boys with certificates of recognition. What time would the boys need to beat in order to earn a certificate of recognition from the fitness association?
A) 398.8 sec B) 384.2 sec C) 515.8 sec D) 501.2 sec

25)
The sampling distribution of the sample mean is shown. If the sample size is n = 9, what is the standard deviation of the population from which the sample was drawn? Round to the nearest thousandth where appropriate.
A) Η = 13.333 B) Η = 4.444 C) Η = 120 D) Η = 360
Statistics Questions

Solution Preview

This material may consist of step-by-step explanations on how to solve a problem or examples of proper writing, including the use of citations, references, bibliographies, and formatting. This material is made available for the sole purpose of studying and learning - misuse is strictly forbidden.

4)
σx 4
σy 11
σ(x+y) 11.7...

This is only a preview of the solution. Please use the purchase button to see the entire solution

Assisting Tutor

Related Homework Solutions

Quantitative Methods for MBAs
Homework Solution
$28.00
Statistics
Finance
Business
Mathematics
Regression
Analysis
Quantitative Methods
Coefficients
Variables
Real Estate Company
Linear Function
Dollars
SPSS Logistic Regression Model Questions
Homework Solution
$50.00
Statistics
Mathematics
Logistic Regression
Functions
Models
SPSS
Vaccination
Harmful Effects
Predictors
Dependency
Variables
Tables
Response Data
Mean
Degrees of Freedom
Calculations
Statistics Questions
Homework Solution
$48.00
Mathematics
Statistics
Probability
Functions
Derivatives
Log-Likehood
Zeros
Population
Hypothesis
Variables
Standard Deviation
Mean
Histograms
Random Numbers
Clinical Biostat
Homework Solution
$45.00
Mathematics
Advanced
Statistics
Biostat
Clinical
Anova
Variance
Hypotheses
Wilcoxon
Steroid Levels
Homework Solution
$40.00
Mathematics
Advanced
Statistics
Steroid
Levels
Variable
Sample
Regression
Estimation
Get help from a qualified tutor
Live Chats