Search & Filtering
A sample size 40 from a non-normal population yielded the sample mean X= 71 and S2 =200. Test H0: µ=72 against H1: µ≠72. Use α= 1%
The Three Sisters Lumber Company is considering buying a machine that planes lumber to the correct thickness. The machine is advertised to produce “6-inch lumber” having a thickness that is normally distributed, with a mean of 6 inches and a standard deviation of 0.1 inch. a. If building standards in the industry require a 99% chance of a board being between 5.85 and 6.15
] Suppose that the Mean and S.D of the tuition fee paid by BS Mathematics students in UMT is 150 and 30 in UDs, respectively. It is assumed that data is normally distributed. If a student is selected at random, find the probability that the amount paid by him is
i) Less than 105
ii) Between 120 to 180
iii) Not between 140 and 160
iv) Greater than 180
v) Between 130 and 160 GIVEN THAT between 140 to 180
vi) Between 120 and 160 OR Between 130 and 180
What composes the sample space
Suppose that the Mean and S.D of the tuition fee paid by BS Mathematics students in UMT is 150and 30 in UDs, respectively. It is assumed that data is normally distributed. If a student is selected at random, find the probability that the amount paid by him is
i) Greater than 105
ii) Not between 120 to 180
iii) Between 140 and 160
iv) Less than 180
v) Between 140 and 160 GIVEN THAT greater than 120
vi) Between 120 and 160ORbetween 140 to 180
Activity: Find the probability given the following Z-scores. Use figure 1 for this activity.
1. 1.64
2. 0.81
3. 3.02
4.-2.73
5.0.09
20
(a) The administration of an inner-city college has generally assumed that the average age of a student is no more than 20 years. The standard deviation of the age of students is known to be 3.6 from previous data. However, lately the students have appeared to be older than before, and some administrators say that the average age could be higher than 20 years. You collect a random age sample of 50 students and calculate a mean of 20.76. At the 90% level of confidence, can you conclude that the average age of students has indeed increased?
A university advertises that 90% of the graduates from their school of science find a job within one year. Researchers want to see if this is really the case and they survey 60 graduates from this university at the end of the first year after graduation and find out that 50 of them were employed. For α=0.10, is there enough evidence to conclude that the one-year employment proportion of this university is different from the advertised 90%?
A cat food company estimates that a salmon based product that they produce has a mean shelf life of 25 months. Some customers claim that the product went bad earlier than the estimated expiration date and the mean shelf life is actually shorter. To test this claim, the company monitors 70 packages of this product and finds that the average shelf life was 23 with a standard deviation of 7 months.
a. Test the customers’ claim for α=0.05
b. Calculate the power of the test if the true mean is 23.5 months
The marks obtained by 6 students in two class tests denoted by x and y, are as follows :
x 6 5 8 10 4 9
y 8 6 7 10 6 8
Obtain the least square regression line of y on x.
