i need help with question 8, 9 ,10 please . A tea drinker\'s society estimates t
ID: 3178015 • Letter: I
Question
i need help with question 8, 9 ,10 please .
A tea drinker's society estimates that the mean consumption of tea by a person in the US is more than 8 gallons per year. In a random sample of 100 people, you find that the mean consumption of tea is 7.9 gallons per year with a standard deviation of 2.67 gallons. At alpha = .07 can you support the society's claim? A computer repairer believes that the mean repair cost for damaged computers is more than $95. To test this claim, you determine the repair costs for 7 randomly selected computers and find that the mean repair cost is $100 per computer with a standard deviation of $42.50. At alpha = .01, do you have enough evidence to support the repairer's claim? A research center estimates that at least 20% of US adults are smokers. In a random sample of 200 adults, 18.5% say that they are smokers. At alpha = .01, is there enough evidence to reject the claim? The mean repair cost for 34 Model A ovens is $50 with a standard deviation of$10, and the mean repair cost for 46 Model B ovens is $60 with a standard deviation of $18. At a significance level of 0.01 can you reject the claim that repair costs for these two models are the same? The mean repair cost for 14 randomly selected small cars is $473 with a standard deviation of$190 and the mean repair cost for 23 midsize cars is $741 with a standard deviation of $205. At a significance level of 0.10, and assuming that the population variances are equal, can you conclude that repair cost is less for small cars than it is for midsize cars? A random sample of 19 residents of County A has a mean annual income of $45, 200 and a standard of random sample of 15 residents of County B has a mean annual income of $40, 700 and a standard deviation of $5, 500. a significance level of 0.10, and assuming that the population variances are not equal, can you conclude that mean income in County A greater than the mean income in County B?Explanation / Answer
Given that,
population mean(u)=8
sample mean, x =7.9
standard deviation, s =2.67
number (n)=100
null, Ho: >8
alternate, H1: <8
level of significance, = 0.07
from standard normal table,left tailed t /2 =1.488
since our test is left-tailed
reject Ho, if to < -1.488
we use test statistic (t) = x-u/(s.d/sqrt(n))
to =7.9-8/(2.67/sqrt(100))
to =-0.375
| to | =0.375
critical value
the value of |t | with n-1 = 99 d.f is 1.488
we got |to| =0.375 & | t | =1.488
make decision
hence value of |to | < | t | and here we do not reject Ho
p-value :left tail - Ha : ( p < -0.3745 ) = 0.3544
hence value of p0.07 < 0.3544,here we do not reject Ho
ANSWERS
---------------
null, Ho: >8
alternate, H1: <8
test statistic: -0.375
critical value: -1.488
decision: do not reject Ho
p-value: 0.3544
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