Search & Filtering
testing and 10 of them happened to be defective. If 4 of the bulbs were randomly selected one
after the other, what is the probability that all the 4 bulbs are defective assumed sampling
without replacements.
A sample of quarterly amounts invested in Ethan-Jaden Company by its employees is depicted in the table below;
(a) According to the Ministry of Health, the height of travellers who were quarantined in Accra for the coronavirus were normally distributed about a mean of 170cm and a variance of 36cm. Find the probability that a traveller selected at random has i) Height between 160cm and 175cm ii) Height above 164cm. iii) Height below 180 cm
(b) The American Automobile Association reports that the average time it takes to respond to an emergency call is 25 minutes. Assume the variable is approximately normally distributed and the standard deviation is 4.5 minutes. If 80 calls are randomly selected, approximately how many will be responded to in less than 15 minutes?
X~N(3,5) standard deviation
1. The following data refers to the price of a good ‘P’ and the quantity of the good supplied, ‘S’.
P 2 7 5 1 4 8 2 8
S 15 41 32 9 28 43 17 40
a. Estimate the linear regression line
b. Estimate the standard errors of
c. Test the hypothesis that price influences supply
A consumer organisation wants to obtain information about , the mean number of drawing pins in the boxes of a certain brand which, according to the label, should contain 100 pins. In nine randomly chosen boxes this organisation finds the following numbers of drawing pins:
90 94 88 92 90 86 94 90 86
(a) (i) Test whether < 100. Take as level of significance a= 0:05.
(ii) Which assumption do you need?
(b) If the true value of u is 101, what type of error did you make in part (a)?
(c) (i) Determine a 90% confidence interval for u
(ii) Is it likely that u= 101?
A computer manufacturer ships laptop computers with the batteries fully charged so that customers can begin to use their purchases right out of the box. In its last model, 85% of customers received fully charged batteries. To simulate arrivals, the company shipped 100 new model laptops to various company sites around the country. Of the 100 laptops shipped, 93 of them arrived reading 100% charged. Do the data provide evidence that this model’s rate is higher than the previous model? Test the hypothesis at a = 0:01. Write down the hypothesis to be tested and show all the steps and calculations
what the 3 digit number in how many three-digit numbers can be formed from the set 0,1,2....9 if repetitions are allowed and the number must be divisible by 25?
A sample of quarterly amounts invested in Ethan-Jaden Company by its employees is depicted in the table below;
Amount Invested
|30<35| 35<40 |40<45| 45<50| 50<55| 55<60| 60<65| 65<70|
Number of employees
|4| 8| 24| 44| 20| 10| 2| 6|
NB: Use two decimal places
i. How many employees invest in the company?
ii. Estimate the mean amount invested.
iii. Calculate the modal amount invested.
iv. Estimate the median amount invested.
v. Estimate the sample standard deviation and interpret it.
The American Automobile Association reports that the average time it takes to respond to an emergency call is 25 minutes. Assume the variable is approximately normally distributed and the standard deviation is 4.5 minutes. If 80 calls are randomly selected, approximately how many
will be responded to in less than 15 minutes?
#332078 on Oct 2022