A polling organization asked a nation-wide random sample of 1600 new brides (those who got married in the past 2 years) the foll
1 answer:
Answer:
It has millions of tickets. On each ticket is written a number a dollar amount. The exact average and SD are unknown but are estimated from the sample to be $20,000 and $5,000 respectively.
Step-by-step explanation:
Given that:
sample size n = 1600
sample mean = 20000
standard deviation = 5000
The objective is to choose from the given option about what most closely resembles the relevant box model.
The correct answer is:
It has millions of tickets. On each ticket is written a number a dollar amount. The exact average and SD are unknown but are estimated from the sample to be $20,000 and $5,000 respectively.
However, if draws are made without replacement, the best estimate of the average amount for the bride will be $20,000
Similarly, the standard error for the sample mean =
the standard error for the sample mean = 125
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Answer:
We conclude that less than or equal to 90% of all orders are mailed within 72 hours after they are received which means the company's claim is not true.
Step-by-step explanation:
We are given that the company claims that more than 90% of all orders are mailed within 72 hours after they are received. The quality control department at the company often takes samples to check if this claim is valid.
A recently taken sample of 175 orders showed that 161 of them were mailed within 72 hours.
<u><em>Let p = percentage of all orders that are mailed within 72 hours.</em></u>
SO, Null Hypothesis, : p
90% {means that less than or equal to 90% of all orders are mailed within 72 hours after they are received}
Alternate Hypothesis, : p > 90% {means that more than 90% of all orders are mailed within 72 hours after they are received}
The test statistics that will be used here is <u>One-sample z proportion</u> <u>statistics</u>;
T.S. = ~ N(0,1)
where, = proportion of orders that were mailed within 72 hours in a sample of 175 =
= 92%
n = sample of orders = 175
So, <u><em>test statistics</em></u> =
= 0.975
The value of the test statistics is 0.975.
<em>Now at 1% significance level, the z table gives critical value of 2.3263 for right-tailed test. Since our test statistics is less than the critical value of z as 0.975 < 2.3263, so we have insufficient evidence to reject our null hypothesis as it will not fall in the rejection region due to which </em><em><u>we fail to reject our null hypothesis</u></em><em>.</em>
Therefore, we conclude that less than or equal to 90% of all orders are mailed within 72 hours after they are received which means the company's claim is not true.
Solution:
The Statement made by company about it's tablet computer,
Average recharge time = 3 Hours
As, to check whether the company claim is illegal or true
A random sample of 50 company tablet computers, and their recharging time is noted.
As, we have taken random sample , so standard deviation will come into consideration whether company claim is true or false.
Mean recharge time of 50 company tablet computers= 2.5 hours
Standard deviation of 50 company tablet computers= 0.3 hours
So, Mean standard deviation =
So, Claim made by company , that its tablet computers have an average recharge time of 3 hours is Approximately true.
As , there is fluctuation of (3 hours - 2.2 hours =3-2.12=48 minutes ) and (3 hours -2.8 hours=3-2.48=12 minutes), which is not so much ,so we can believe on this company and buy the product (that is tablet computers) of this company.