X ~ N(70, 14). Suppose that you form random samples of 25 from this distribution. Let X bar be the random variable of averages. Let ΣX be the random variable of sums. Find the 40th percentile
In: Math
In a study of 798 randomly selected medical malpractice lawsuits, it was found that 476 of them were dropped or dismissed. Use a 0.01 significance level to test the claim that most medical malpractice lawsuits are dropped or dismissed. What is the correct hypothesis to be tested? What is the test statistic? (Round to two decimal places as needed.) What is the P-value? What is the conclusion about the null hypothesis? What is the final conclusion?
In: Math
A Washington resident was curious whether the color of roofing materials had any association with snow accumulation in Washington. One day after a surprising October snowfall, they went to the top of the Capitol Building and examined the 500 visible distinct roofs with a pair of binoculars, and found 340 dark colored roofs and 160 light colored roofs. Of the dark colored roofs, 80 still had visible snow accumulation, while 70 of the light colored roofs still had visible snow.
(a) Perform a hypothesis test at the 5% level of significance to determine if there is evidence of a difference in the proportion of roofs with visible snow accumulation between dark colored roofs and light colored roofs. (Be sure to state your hypotheses and show your computations.)
(b) Create a 95% confidence interval for the difference in proportion of dark and light roofs with snow accumulation.
(c) State one reason why the resident’s observations may not be independent.
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4. Is OLS estimator unbiased when we use time series data? Why or why not? Are standard errors still valid if there is serial correlation? Why or why not?
In: Math
Determine the sample size necessary to estimate p for the following information. a. E = 0.01, p is approximately 0.60, and confidence level is 96% b. E is to be within 0.04, p is unknown, and confidence level is 95% c. E is to be within 5%, p is approximately 54%, and confidence level is 90% d. E is to be no more than 0.01, p is unknown, and confidence level is 99%
In: Math
The traffic control system inside Riyadh city is not meeting the
expectations of the city traffic police. The system is to be
updated within a few weeks to incorporate the traffic intensity,
the weather conditions and the VIP movements etc. The entire
project is to be completed within 10 weeks as per the following
schedule:
|
Task ID |
Task |
Allocated Time (Weeks) |
Budget (SAR) |
|
TID-10 |
Requirements elicitation |
1 |
10,000 |
|
TID-11 |
Use-case Development |
1 |
10,000 |
|
TID-12 |
Process Model Development |
1 |
10,000 |
|
TID-13 |
Data Model Development |
1 |
10,000 |
|
TID-20 |
Architecture-Level Design |
1 |
10,000 |
|
TID-21 |
User-Interface Design |
1 |
10,000 |
|
TID-22 |
Algorithm Design |
1 |
10,000 |
|
TID-23 |
Data Storage Design |
1 |
10,000 |
|
TID-30 |
Programming |
1 |
10,000 |
|
TID-31 |
Quality Assurance |
1 |
10,000 |
At the end of Week 7 of the project you have completed only first six tasks (i.e. you just finished, TID-21 i.e. Data Model Development) with a total of SAR 67,500 spent to date. The Interior Minister asks you to produce a report on the status of project work with the help of earned value method. In particular you are asked to include answers to the following questions in your report:
Use the earned value management (EVM) in the given scenario
answering each of the abovementioned question separately.
thank you for time and effort
In: Math
In: Math
Suppose the heights of 18-year-old men are approximately normally distributed, with mean 70 inches and standard deviation 1 inches.
(a) What is the probability that an 18-year-old man
selected at random is between 69 and 71 inches tall? (Round your
answer to four decimal places.)
(b) If a random sample of seven 18-year-old men is selected, what
is the probability that the mean height x is between 69
and 71 inches? (Round your answer to four decimal places.)
(c) Compare your answers to parts (a) and (b). Is the probability
in part (b) much higher? Why would you expect this?
-The probability in part (b) is much higher because the standard deviation is smaller for the x distribution.
-The probability in part (b) is much higher because the standard deviation is larger for the x distribution.
-The probability in part (b) is much lower because the standard deviation is smaller for the x distribution.
-The probability in part (b) is much higher because the mean is smaller for the x distribution.
-The probability in part (b) is much higher because the mean is larger for the x distribution.
In: Math
Scenario 2: In a city of 100,000 people, there were last year 1000 deaths and 1500 live births (none were multiple births), of which 1200 infants survived to see their first birthday. Three mothers died in childbirth. Using the Week 3 PowerPoint for definitions, calculate the answers to the questions below. (http://adph.org/healthstats/assets/Formulas.pdf )
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|
In: Math
A poll conducted by GfK Roper Public Affairs and Corporate Communications asked a sample of 1007 adults in the United States, "As a child, did you ever believe in Santa Claus, or not?" Of those surveyed, 84% said they had believed as a child. Consider the sample as an SRS. We want to estimate the proportion p of all adults in the United States who would answer that they had believed to the question "As a child, did you ever believe in Santa Claus, or not?"
(a) Find a 90% confidence interval (±±0.0001) for p based on this sample.
The 90% confidence interval is from __ to ___
b) Find the margin of error (±±0.0001) for 90%.
The margin error is ___
(c) Suppose we had an SRS of just 100 adults in the United States.
What would be the confidence interval (±±) for 95% confidence?
The 50 % confidence interval (+) is from __ to __
(d) How does decreasing the sample size change the confidence interval when the confidence level remains the same?
a. Decreasing the sample size creates a wider interval
b.Decreasing the sample size creates a less wide interval.
In: Math
| The American Council of Education reported that 47% of college freshmen earn a degree and graduate within 5 years. | ||||||
| Assume that graduation records show women make up 50% of the students who graduated within 5 years, | ||||||
| but only 45% of the students who did not graduate within 5 years. | ||||||
| The students who had not graduated withing 5 years either dropped out or were still working on their degrees. | ||||||
| Students earn a degree and graduate within 5 years | 47% | |||||
| Women student graduate within 5 years | 50% | |||||
| Percentage of students who are women and did not graduate within 5 years | 45% | |||||
| Let: | A1 | = | the student graduated within five years | |||
| A2 | = | The student did not graduate within five years | ||||
| W | = | the student is a woman | ||||
| M | = | the student is a man | ||||
| Joint | and | Marginal | Probabitilities | |||
| A1 (in 5) | A2 (not in 5) | |||||
| Women (W) | ||||||
| Men (M) | ||||||
| (1) | (2) | (3) | (4) | (5) | ||
| Prior | Conditional | Joint | Posterior | |||
| Events | Probabilities | Probabilities | Probabilities | Probabilities | ||
| P( Ai ) | P( W | Ai ) | P( Ai /\ W ) | P( Ai | W ) | |||
| A1 | ||||||
| A2 | ||||||
| P( W ) = | ||||||
In: Math
A presidential candidate's aide estimates that, among all college students, the proportion p who intend to vote in the upcoming election is at most 75 % . If 217 out of a random sample of 270 college students expressed an intent to vote, can the aide's estimate be rejected at the 0.05 level of significance? Perform a one-tailed test. Then fill in the table below.
Null Hypothesis
Alternative Hypothesis
type of test statistic
Value of the test statistic
the critical value at the .05 level of significance
Can we reject the aide's estimate that the proportion of college students who intend to vote is at most 75%?
In: Math
Each member of a random sample of 16 business economists was asked to predict the rate of inflation for the coming year. Assume that the predictions for the whole population of business economists follow a normal distribution with standard deviation 2.1%
a. The probability is 0.10 that the sample standard deviation is bigger than what number?
b. The probability is 0.01 that the sample standard deviation is less than what number?
c. Find any pair of numbers such that the probability that the sample standard deviation that lies between these numbers is 0.975.
In: Math
question about R:
The vectors state.name, state.area, and state.region are pre-loaded in R and contain US state names, area (in square miles), and region respectively.
(a) Identify the data type for state.name, state.area, and state.region.
(b) What is the longest state name (including spaces)? How long is it?
(c) Compute the average area of the states which contain the word “New” at the start of the state name. Use the function substr().
(d) Use the function table() to determine how many states are in each region. Use the function kable() to include the table in your solutions. (Notes: you will need the R package knitr to be able to use kable().
In: Math
5.1 Combination and permutation
a) 5C2
b) 5!
c) Five different drugs, A, B, C, D, and E, can be used to treat a disease in different combinations. If a physician uses two of them to treat patients, how many combinations are possible? List all such combinations.
d) Four different exercises, A, B, C, and D, are recommended for an injury recover therapy program. The therapists want to know whether there is a different treatment effect using i) just one; ii) any two; or iii) any three of the therapies. How many treatment regimens can a therapist choose from? What are they?
e) If the order matters in d), if therapists were to select two exercises out of four, how many treatment options would the therapists have? What are they?
In: Math