Statistics and Probability Answers

Questions: 18 160

Answers by our Experts: 16 242

Need a fast expert's response?

Submit order

and get a quick answer at the best price

for any assignment or question with DETAILED EXPLANATIONS!

Search & Filtering

If X is binomially distributed with mean 3.20 and variance 1.152, find the complete binomial probability distribution


Suppose that the tires of a certain brand have mean life 25,430 km and standard

deviation 1,800 km.

(a) If a tire is randomly selected, what is the probability that its life is longer than 25,000 km?

(b) Determine the minimal sample size needed so that the probability of the sample mean life longer than 25,000 km is at least 0.97. [15 marks] 



In the manufacturing process, a compact disc is acceptable if its diameter is between 120.00mm and 120.20mm. A new machine produces compact discs whose diameters are normally distributed with mean 120.11mm and standard deviation 0.05mm.

(a) What is the probability that a randomly selected compact disc is acceptable?

(b) If four compact discs are randomly selected, what is the probability that at least two of them are not acceptable?

THX!



1.      What percentage of the scores in a normal distribution lie below a z-score of 1.65?


a.      1.65%  b. 15%    c. 45%  d. 60%  e. 75%  f. 90%  g. 95%


In a survey taken 10 years ago, it was found that 10% of customers of a supermarket brought along their own shopping bags. A recent survey aimed to prove that the current percentage of customers bringing along their own shopping bags is different from 10%. In the survey, it was found that 92 of the 1000 customers surveyed brought along their own shopping bags. We want to test the claim that the current percentage is not 10%, at the 5% significance level.
(a) State the appropriate null and alternative hypothesis. (2)
(b) State and calculate the appropriate test statistic. (8)
(c) Determine the critical value of the test or the pà ƒ ƒ ¢ € “value of the test. (4)
(d) State whether or not you reject the null hypothesis, giving the reason. (3)
(e) Draw an appropriate conclusion.

Four groups of 4 patients each were subjected to four different types of treatment for the same ailment. The following data are on the number of days that elapsed before they were completely cured. What conclusions may be drawn about the four types of treatment?

Patient 1: Treatment A is 10, Treatment B is 11, Treatment C is 3. Treatment D is 6

Patient 2: Treatment A is 9, Treatment B is 11, Treatment C is 4. Treatment D is 10

Patient 3: Treatment A is 6, Treatment B is 18, Treatment C is 5. Treatment D is 8

Patient 4: Treatment A is 7, Treatment B is 6, Treatment C is 7. Treatment D is 11



The number of fishing rods selling each day is given below. Perform analyses of the time series to determine which model should be used for forecasting.

 

a. 3 day moving average analysis

b. 4 day moving average analysis

c. 3 day weighted moving average analysis with weights w1=0.2, w2=0.3 and w3=0.5 with w1 on the oldest data

d. exponential smoothing analysis with a = 0.3.

e. Which model provides a better fit of the data?

f. Forecast day 13 sales of fishing rods using the model chosen in part (e).

Day

Rods sold

1 60

2 70

3 110

4 80

5 70

6 85

7 115

8 105

9 65

10 75

11 95

12 85


in a certain school is known to be normally distributed with a mean of P70 and a standard deviation of P20. A random sample of 16 students will be taken.

What are the two values that are within P10 of the true mean?


Consider that in a population of Filipino adults ages 18 to 65, Body Mass Index (BMI) is normally distributed with a mean of 28 and a standard deviation of 6. What is the BMI mark of the bottom 20% of the distribution of this population? *


the average length of time for students to register for summer classes at a certain college has been 50 minutes. A new registration procedure using modern computing machines is being tried. If a random sample of 35 students had an average registration time of 42 minutes with a standard deviation of 11.9 minutes under the new system, test the hypothesis that the population mean is now less than 50 minutes, using 0.01 level of significance. Assume the population of times to be normal.
LATEST TUTORIALS
APPROVED BY CLIENTS