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N&M magazine believes that it has a 38% share of the national female readership market of women’s magazines. When 2 000 readers of women’s magazines were randomly selected and interviewed, 700 stated that they read N&M regularly.
(3)
2.1.1Does the sample evidence support their claim? Explain.(5)
2.1.2 What is the population of interest in this case?(2)
2.1.3What is the sample in this case?
(2)
2.1.4 What percentage of readers interviewed read N&M magazine regularly? Is this a statistic or a parameter? Explain.
2.1.5 What does the value 38% represent in the above case? Explain.
Identify the region or are under tge normal cyrve corresponds to the right of z is equal to 1.36
B. Identify if it is two-tailed or one-tailed
C. Get the critical values from the test statistic table.
D. Sketch the critical regions.
1. The principal claims that 6 of every 10 learners have access to internet and social networking sites. Upon verification, only 40 out of 70 learners have access to internet & social networking sites. At 95% confidence,is the claim true?
2. The health worker claims that less than 30% of covid-19 cases are asymptomatic. Upon looking at 100 cases, it was found out that 19 of which are asymptomatic. At 99% confidence level,is the claim true?
B.Formulate the appropriate null and alternative hypotheses;and
C.Compute for the test-statistic value for population proportion.
1.The principal claims that 6 of every 10 learners have access to internet and social networking sites.Upon verification,only 40 out of 70 learners have access to internet and social networking sites.At 95% confidence,is the claim true?
2.The SSG Presidential claims that more than 80% of the students loves the new uniform design.50 students were asked about the new uniform design and 42 said they love it.Using 0.01 level of significance,is the claim true?
3.The health worker claims that less than 30% of COVID-19 cases are asymptomatic.Upon looking at 100 cases ,it was found out that 19 of which are asymptomatic.At 99% confidence level,is the claim true?
Example 2.11 Suppose that the average number of hours a personal computer is used for entertainment is two hours per day. Assume the times for entertainment are normally distributed and the standard deviation is half an hour.
a. Find the probability that a personal computer is used for entertainment more than 1 hour per day
b. Find the probability that a personal computer is used for entertainment more than 4 hours per day
c. Find the probability that a personal computer is used for entertainment between 1 and 4 hours per day
· Variance of returns is just one possible risk measure, i.e. different risk measures can be employed when dealing with returns of risky asset
A manufacturer of a lightbulb claimed that its lightbulbs have a mean lifetime of 700 hours with a standard deviation of 120 hours. You purchased 144 of these lightbulbs with the idea that you would purchase more if the mean lifetime of your sample were more than 680 hours. What is the probability that you will not buy again from this manufacturer?
Assume that a weather forecast for tomorrow states that it rains in Johannesburg with probability 0,2 and it rains in Pretoria with probability 0,3. Assume further that we are told that if it does rain in Pretoria, then it rains in Johannesburg with 0.8 probability. Calculate the following
a) The probability that it rains in both Pretoria and Johannesburg.
B) The probability that it rains in at least one of the cities.
Problem 2.
According to the study conducted last year, the average monthly consumption of senior high school students for mobile phone loads is P400. A group of statistics students believes that the amount was increased in the last quarter. Is there a reason to believe that the amount has really increased if the sample of 20 students has an average monthly expenses of P450 for mobile phone loads. Use 0.05 level of significance. Assume that the population standard deviation is P70.
Problem 1.
A principal at a certain school claims that the students in his school are above average intelligence. A random sample of thirty students IQ scores have a mean score of 112.5. Is there sufficient evidence to support the principal’s claim? The mean population IQ is 100 with a standard deviation of 15. Use 0.01 level of significance.
Let X be a continuous random variable with density function below.
"x = \\begin{cases}\n \\frac{x}{2}, &\\text{for } 0 \u2264 x \u2264 2 \\\\\n 0, &\\text{otherwise } \n\\end{cases}"
Find E [|X-E[X]|].
#340153 on Dec 2023