Search & Filtering
A mass of 150g was hung in turn from 250 pieces of a certain yarn,
and 12 of the pieces broke. A mass of 200 g then hung from the
previously unbroken pieces and further 213 pieces broke.
Assuming that yarn strength is distributed normally, estimate the
mean and standard deviation of the yarn’s strength.
t is relatively common for fish to be mislabeled in supermarkets and even in restaurants. The table below shows the results of a study where a random sample of 156 fish for sale were collected and genetically tested. The researchers classified each sample as being labeled properly or being mislabeled. What fraction of smoked fish in the sample were mislabeled? Choose the closest answer.
| Smoked Not Smoked | Total
Mislabeled | 28 11 | 39
Properly labeled | 8 109 | 117
Total | 36 120 | 156
9%
18%
28%
78%
72%
?
The distribution of exam scores (ranging from 0 - 100%) where the mean score is 75%, the standard deviation is 12%, and the median is 78% is most likely
left skewed
right skewed
symmetric
uniform
?
Direction: Solve the problem below.
1. A population consists of three numbers (3, 6, 9). Consider all possible samples of size
2 which can be drawn without replacement from the population. Find the following:
a. Population mean
b. Population variance
c. Populations standard deviation
d. Mean of the sampling distribution of the means
e. Variance of the sampling distribution of the means
f. Standard deviation of the sampling distributions of the means.
A course in Mathematics is taught to 12 students by a conventional class room procedure. A second group of 10 students was given the same course by means of programmed materials. At the end of the semester the same examination was given to each group. The 12 students meeting in the classroom made an average grade of 85 with a standard deviation of 4. While the 10 students using programmed materials made an average of 81 with standard deviation of 5. Test the hypothesis using 0.01 level of significance. (Assuming Normal Distribution)
Weekly revenues for a particular curry puff seller in Ang Mo Kio are normally distributed with mean $11,480 and standard deviation $1,165. For how many weeks per year would you expect revenues to be less than $8,150?
