Search & Filtering
Val wanted to know the average shearing strength, in pounds (lbs.), of a particular kind of rivet sold in a hardware store. He tested 20 rivets as samples and got the following results.
518
490
513
598
510
532
512
455
500
512
501
487
498
496
500
498
515
520
497
502
Construct a confidence interval for the population mean using 99% confidence.
A teacher conducted a study to know if blended leaming improves the students performances. A class of 25 students of Grade 11 was surveyed and found out that their mean score was 83 with a standard deviation of 3. A
study from other country revealed that = 80 with a standard deviation of 4. Test the hypothesis at 0.10 level of significance.
Examine the series for convergence for summation of ((-1)^(n-1) sin(nx))/n^3
1. in building an arena, steel bars with a mean ultimate tenslie strength of 400 Megapascal (MPa) with a variance of 81 MPa were delivered by the manufacturer. The project engineer tested 50 steel bars and found out that the mean ultimate tensile strength is 390 MPa. The decision for the extension of the contract with the manufacturer depends on the engineer. Test the hypothesis whether or not there is no significant difference between the two means using a two-tailed with u = 0.01.
a. What are the appropriate hypotheses for the two-tailed test?
b. What is the test statistic to be used and the reasons for its selection? G. What is the critical value c?
d. What is the value of the test statistic or the computed value?
e. Formulate a conclusion about the given situation.
1. in building an arena, steel bars with a mean ultimate tenslie strength of 400 Megapascal (MPa) with a variance of 81 MPa were delivered by the manufacturer. The project engineer tested 50 steel bars and found out that the mean ultimate tensile strength is 390 MPa. The decision for the extension of the contract with the manufacturer depends on the engineer. Test the hypothesis whether or not there is no significant difference between the two means using a two-tailed with u = 0.01.
a. What are the appropriate hypotheses for the two-tailed test?
b. What is the test statistic to be used and the reasons for its selection? G. What is the critical value c?
d. What is the value of the test statistic or the computed value?
e. Formulate a conclusion about the given situation.
A population of values has a normal distribution with u = 56.1 and o = 57.7. If a random sample of size n = 20 is selected,
- Find the probability that a single randomly selected value is greater than 63.8. Round your answer to four decimals
P(X > 63.8) =
-Find the probability that a sample of size n = 20 is randomly selected with a mean greater than
P(M > 63.8) =
A population of values has a normal distribution with u = 91.9 and o = 38.4. A random sample of size n = 232 is drawn.
- What is the mean of the distribution of sample means? Ux=
-What is the standard deviation of the distribution of sample means? Round your answer to two decimal places. Ox=
The mean length of certain construction lumber is supposed to be 8.5 feet. A random
sample of 21 pieces of such lumbers gives a sample mean of 8.3 feet and a sample
standard deviation of 1.2 feet. A builder claims that the mean of the lumber is different
from 8.5 feet. Does the datasupport the builder's claim at a= 0.05?
Step:
1.State the null and alternative hypothesis concerning the population mean, "\\mu" and the type of test to be used.
2.Specify the level of significance "\\alpha"
3.State the decision rule
4.Collect the data and perform calculations.
5. Make a statistical decision.
6.State the conclusion.
A supermarket boasts that checkout times for customers are never more than 15 minutes. A random sample of 36 costumers reveals a mean checkout time of 17 minutes with a standard deviation of 3 minutes. What can you conclude about the supermarket’s boast at the 0.05 level?
A coin is tossed 10 times. Find the probability that at least three are tails.
