Search & Filtering
A nutrition store in the mall is selling “Memory Booster,” which is a concoction of herbs and minerals that is intended to improve memory performance, but there is no good reason to think it couldn't possibly do the opposite. To test the effectiveness of the herbal mix, a researcher obtains a sample of 8 participants and asks each person to take the suggested dosage each day for 4 weeks. At the end of the 4-week period, each individual takes a standardized memory test. In the general population, the standardized test is known to have a mean of μ = 7. (Set the significance level➔ = .05)
Find P( -1.2 < Z < -0.2 )
Given: Margin of error (d)= 2.19, Confidence interval (CI) of population mean = 90%, and population standard deviation (σ)= 5 solve for the appropriate sample size.
In a study made on time and motion, it was found out that a certain manual work can be finished at an average time of 40 minutes with a standard deviation of 18 minutes. A group of 16 workers is given a special training and then found to average only 35 minutes. Can we conclude that the special training can speed up the work using a 0.05 level?
2. A random sample of 40 boys showed a mean weight of 120 lbs. with a standard deviation
of 12lbs. The standard weight for their age category is about 130lbs. Test the hypotheis that the selected boys are significantly lighter than the standard weight at0.01 level of siginificance.
Construct the sampling distribution of the sample mean for the population that consists of the scores 15, 18, 11, 14, 17, with a sample size of 3. Compute as well the mean of the sampling distribution using the expected value of the distribution and verify the result by computing for the population mean.
it is claimed that the average monthly income of chemical engineers last year was P27,900.00 A random sample of 36 chemical engineers is selected and it is found out that the average monthly salary is P28,000.00 Using a 0.05 level of significance can it be concluded that there is an increase in the average monthly income of chemical engineers? Assume that the population standard deviation is P250.50
Find the mean, variance and standard deviation of the following measures 2,5,6,3,9,10,12
2. The population mean length of a chocolate wafer stick is 86 mm long with a standard deviation of 6 mm. A sample of 20 sticks are taken. What is the probability that
a. the sample mean is not less than 84 mm?
b. the sample mean is not more than 87 mm?
c. the sample mean differs from the population mean by at most 4 mm?
The manufacturer of a new drug claims that it will lower
blood pressure by 13 points on the average. When the drug was
administered to 6 patients, the following drops in blood pressure
were registered: 12, 8, 15, 9, 10 and 16. Is the claim sustained at
the 0.05 level of significance.
