Question

In: Statistics and Probability

A marketing manager for a cell phone company claims that more than 55% of children aged...

A marketing manager for a cell phone company claims that more than 55% of children aged 8−12 have cell phones. In a survey of 802 children aged 8−12 by the National Consumers League, 449 of them had cell phones. Can you conclude that the manager’s claim is true? Use the α = 0.01 level of significance

Expert Solution

Solution :

Given that,

= 0.55

1 - = 0.45

n = 802

x = 449

Level of significance = = 0.01

Point estimate = sample proportion = = x / n = 0.560

This a right (One) tailed test.

Ho: p = 0.55

Ha: p 0.55

Test statistics

z = ( - ) / *(1-) / n

= ( 0.560 - 0.55) / (0.55*0.45) /802

= 0.561

P-value = P(Z>z)

= 1 - P(Z <z )

= 1- P(Z < 0.561)

= 1 - 0.7126

= 0.2874

The p-value is p = 0.2874, and since p = 0.2874 > 0.01, it is concluded that the null hypothesis is fail to reject.

Conclusion:

It is concluded that the null hypothesis Ho is fail to reject. Therefore, there is not enough evidence to claim that the A

marketing manager for a cell phone company claims that more than 55% of children aged 8−12 have cell phones. at 0.01

level of significance.

orchestra answered 2 years ago

Calculate the test statistic. A research company claims that no more than 55% of Americans regularly...

Calculate the test statistic. A research company claims that no more than 55% of Americans regularly watch FOX News. You decide to test this claim and ask a random sample of 425 Americans if they watch this network regularly. Of the 425 sampled, 255 respond yes. Calculate the test statistic for the hypothesis test. a) -2.07 b) 1.645 c) -1.96 d) 2.07 e) None of the above.

A company that produces cell phones claims its standard phone battery lasts longer on average than...

A company that produces cell phones claims its standard phone battery lasts longer on average than other batteries in the market. To support this claim, the company publishes an ad reporting the results of a recent experiment showing that under normal usage,their batteries last at least 35 hours. To investigate this claim, a consumer advocacy group asked the company for the raw data. The company sends the group the following results: 35, 34, 32, 31, 34, 34, 32, 33, 35,...

A researcher claims that more than 55% of adults believe it is very likely that life...

A researcher claims that more than 55% of adults believe it is very likely that life exists on other planets. In a survey of 1000 adults, 585 say it is very likely that life exists on other planets. At α = 0.05, can you support the researcher’s claim?

A research center claims that more than 55% of U.S. adults think that it is essential...

A research center claims that more than 55% of U.S. adults think that it is essential that the United States continue to be a world leader in space exploration. In a random sample of 25 U.S. adults, 64% think that it is essential that the United States continue to be a world leader in space exploration. At a = 0.01, is there enough evidence to support the center’s claim? (Adapted from Pew Research Center)

Calculus The marketing department for a cell phone telephone company has determined that the demand for...

Calculus The marketing department for a cell phone telephone company has determined that the demand for their phone obeys the following relationship: p= -0.02+200 , (0 ≤ p ≤10,000) , where p denotes the phone’s unit price (in dollars) and x the quantity demanded. This type of question is much easier when you use your calculator, I just need to know what you did when you give me an answer using it, (a) Express the revenue as a function of...

A bank manager claims that the median number of customer per day is no more than...

A bank manager claims that the median number of customer per day is no more than 440. A teller doubts the accuracy of this claim. The number of bank customers per day for 16 randomly selected days are listed below 410, 416, 416, 420, 430, 433, 437, 440, 450, 455, 455, 460, 463, 465, 465, 470 At the 0.05 significance level, test the bank manager's claim. The test statistic x is______ The x-critical value is________

As a newly hired manager of a company that provides cell phone service, you want to...

As a newly hired manager of a company that provides cell phone service, you want to determine the percentage of adults in your state who live in a household with cell phones and no land-line phones. How many adults must you survey? Assume that you want to be 90% confident that the sample percentage is within 4 percentage points of the true population percentage. In a test of effectiveness of garlic for lowering cholesterol, 47 subjects were treated with Garlicin,...

A company claims their new cell phone model has a mean battery life of 60 hours....

A company claims their new cell phone model has a mean battery life of 60 hours. A consumer group suspects this claim is exaggerated so they record the battery life of 100 randomly selected cell phones of this model and conduct a hypothesis test. The sample gives a mean life of 58 hours and a standard deviation of 10. Use this information to answer the following questions. a. What is the null hypothesis about the population mean battery life? b....

A cell phone tower manufacturer more than doubled its EPS by changing depreciation methods. In justifying...

A cell phone tower manufacturer more than doubled its EPS by changing depreciation methods. In justifying the change, management supported the change as follows: In comparison to direct competitors, the previous depreciation method was more conservative and thus had a negative impact on earnings. Comment on the appropriateness of making accounting changes to fulfill financial reporting objectives, Consider relevant ethical issues as well as GAAP in your response.

A cell phone company states that the mean cell phone bill of all their customers is...

A cell phone company states that the mean cell phone bill of all their customers is less than $83. A sample of 19 customers gives a sample mean bill of $82.17 and a sample standard deviation of $2.37. At ? = 0.05 , test the company’s claim? 1). State the hypothesis and label which represents the claim: : H 0 : H a 2). Specify the level of significance  = 3). Sketch the appropriate distribution, find and label the...