In March 2025
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APPLICATION:
an experimental study was conducted by a researcher to
determine if a new time slot has an effect on the performance
of pupils in mathematics. Fifteen randomly selected learners
participated in the study. Toward the end of the investigation, a
standardized assessment was conducted. The sample mean x̄= 75 and s=5. In standardization of the test, the mean was
65 and standard deviation was 8. Based on the evidence at
hand, is the new time slot effective? Use α = 0.05.
The CEO of a battery manufacturing company claimed that their batteries would last an average of 280 hours under normal use. A researcher randomly selected 20 batteries from the production line and tested them. The tested batteries had a mean life span of 250 hours with a standard deviation of 40 hours. Do we have enough evidence to suggest that the claim of an average of 280 hours is false?
The CEO of a battery manufacturing company claimed that their batteries would last an average of 280 hours under normal use. A researcher randomly selected 20 batteries from the production line and tested them. The tested batteries had a mean life span of 250 hours with a standard deviation of 40 hours. Do we have enough evidence to suggest that the claim of an average of 280 hours is false?
There is a spinner with 15 equal areas, numbered 1 through 15. If the spinner is spun one time, what is the probability that the result is a multiple of 3 or a multiple of 4?
An association of City Mayors conducted a study to determine the average number of times
a family went to buy necessities in a week. They found that the mean is 4 times in a week. A
random sample of 20 families were asked and found a mean of 5 times in a week and a
standard deviation of 2. Use 5% significance level to test that the population mean is not
equal to 4. Assume that the population is normally distributed.
On average, four students visits the Mathematics and Statistics tutoring centre during a 5-minute period.
(a) Calculate the probability that three students visit the center during a 5- minute period.
(b) During a ten-minute period, what is the probability that at least 4 students visit the centre?
two fair number cubes, labeled 1 through 6, are rolled and the results are recorded. how many outcomes are in the sample space?
Married People In a specific year 53.7% of men in the United States were married and 50.3% of women were married. Random samples of 300 men and 300 women found that 178 men and 139 women were married (not necessarily to each other.) At the 0.05 level of significance can it be concluded that the proportion of men who were married is greater than the proportion of women who were married?
According to a survey, only 15% of customers who visited the web site of a major retail store made a purchase. Random samples of size 50 are selected. Find the mean of all the sample proportions of customers who will make a purchase after visiting the web site
In a dental surgery conducted by a country dental health team, 500 adults were asked to
give the reason for their last visit to a dentist. Of the 220 who had less than a high-school
education or better, 150 stated that they went for preventative reasons. Construct a 95
percent confidence interval.
