# Let X be normally distributed with mean 120 and standard deviation 10. What is the probability P(X < 125|X < 130)? 12 B) 0.42 C) 0.43 D) 0.04 E) 0.82 Ten students are taking a course at NTNU. Each student has a probability of 0.5 of showing up at any given lecture and they act independently. What is the probability that exactly four students attend a given lecture? 246 B) 0.623 C) 0.011 D) 0.377 E) 0.205 Let X be a discrete random variable with distribution x 0 1 2 3 P(X = x) 0.1 0.5 0.3 0.1 What is the expected value of X? 5 B) 1.4 C) 2.6 D) 0.8 E) 1.0 Let X be a discrete random variable with distribution x 0 1 2 3 P(X = x) 0.1 0.5 0.3 0.1 What is the standard deviation of X? 5 B) 1.4 C) 2.6 D) 0.8 E) 1.0

Find the correct answer to each question. The calculation need not be included.

1. Let X be normally distributed with mean 120 and standard deviation 10. What is the probability P(X < 125|X < 130)?
1. 12 B) 0.42 C) 0.43 D) 0.04 E) 0.82
2. Ten students are taking a course at NTNU. Each student has a probability of 0.5 of showing up at any given lecture and they act independently. What is the probability that exactly four students attend a given lecture?
1. 246 B) 0.623           C) 0.011           D) 0.377          E) 0.205
3. Let X be a discrete random variable with distribution

x   0          1          2          3

P(X = x) 0.1     0.5       0.3       0.1

What is the expected value of X?

1. 5 B) 1.4   C) 2.6   D) 0.8  E) 1.0
1. Let X be a discrete random variable with distribution

x   0          1          2          3

P(X = x) 0.1     0.5       0.3       0.1

What is the standard deviation of X?

1. 5 B) 1.4   C) 2.6   D) 0.8  E) 1.0

Problem 2

A randomized clinical trial was performed to compare two dierent treatments for tennis elbow: steroid injection and physiotherapy. Six weeks after treatment the pain-free grip force x was measured. Assume that x is normally distributed, with mean µ1 and standard deviation σ1 for pasients given steroid injection, and with mean µ2 and standard deviation σ2 for patients given physiotherapy.

1. a) Propose a test of whether mean pain-free grip force for patients given steriods is equal to that of patients given physiotherapy. State the null hypothesis and the alternative hypothesis.

A number n1 = 62 patients were given steroid injections. The sample average for pain-free grip force was x¯1 = 83.6 and the sample standard deviation was s1 = 22.9. A number n2 = 65 patients were given physiotherapy. The sample average for pain-free grip force was x¯2 = 70.2 and the sample standard deviation was s2 = 25.4.

1. Test whether mean pain-free grip force for patients given steriods and mean pain-free grip force for patients given physiotherapy are equal. Use signicance level 5 %.
2. Find a 95% condence interval for µ1 µ2. How do you interpret this interval?

Problem 3

Children in the fourth, fth and sixth grade were asked what they considered important at school. The possible answers were ’good marks’, ’success in sports’ and ’popularity’.

The answers distributed as below:

4th grade      5th grade        6th grade        total good marks        49       50        69        168 success in sports 19       22        28      69 popularity   24       36        38        98 totalt          92       108      135      335

1. Propose a test of whether answer and grade are associated, stating the null hypothesis and the alternative hypothesis.
2. Perform the proposed test at the 5% signicance level.
3. Find a 95% condence interval for the proportion that answers ’good marks’ among 6 th graders.

## Calculate the price of your order

550 words
We'll send you the first draft for approval by September 11, 2018 at 10:52 AM
Total price:
\$26
The price is based on these factors:
Academic level
Number of pages
Urgency
Basic features
• Free title page and bibliography
• Unlimited revisions
• Plagiarism-free guarantee
• Money-back guarantee
• 24/7 support
On-demand options
• Writer’s samples
• Part-by-part delivery
• Overnight delivery
• Copies of used sources
• Expert Proofreading
Paper format
• 275 words per page
• 12 pt Arial/Times New Roman
• Double line spacing
• Any citation style (APA, MLA, Chicago/Turabian, Harvard)

# Our guarantees

Delivering a high-quality product at a reasonable price is not enough anymore.
That’s why we have developed 5 beneficial guarantees that will make your experience with our service enjoyable, easy, and safe.

### Money-back guarantee

You have to be 100% sure of the quality of your product to give a money-back guarantee. This describes us perfectly. Make sure that this guarantee is totally transparent.

### Zero-plagiarism guarantee

Each paper is composed from scratch, according to your instructions. It is then checked by our plagiarism-detection software. There is no gap where plagiarism could squeeze in.

### Free-revision policy

Thanks to our free revisions, there is no way for you to be unsatisfied. We will work on your paper until you are completely happy with the result.

### Privacy policy

Your email is safe, as we store it according to international data protection rules. Your bank details are secure, as we use only reliable payment systems.

### Fair-cooperation guarantee

By sending us your money, you buy the service we provide. Check out our terms and conditions if you prefer business talks to be laid out in official language.

Uncategorized