A researcher knew that before cell phones, a person made on average 2.7 calls pe

Question

A researcher knew that before cell phones, a person made on average 2.7 calls per day. He believes that the number of calls made per day today is higher. He selects a random sample of 33 individuals who use a cell phone and asks them to keep track of the number of calls that they made on a certain day. The mean was 3. Ata = 0.10, is there enough evidence to support the researcher's claim? The standard deviation for the population found by a previous study is 0.8. Assume that the variable is normally distributed. Use the critical value method with tables. Part 1 State the hypotheses and identify the claim with the correct hypothesis. 2.7 not claim 2.7 claim test. Part 2 out of 5 Find the critical value. Round the answer to two decimal places. Critical value is CHECK NEXT

Explanation / Answer

Given that,
population mean(u)=2.7
standard deviation, =0.8
sample mean, x =3
number (n)=33
null, Ho: =2.7
alternate, H1: >2.7
level of significance, = 0.1
from standard normal table,right tailed z /2 =1.28
since our test is right-tailed
reject Ho, if zo > 1.28
we use test statistic (z) = x-u/(s.d/sqrt(n))
zo = 3-2.7/(0.8/sqrt(33)
zo = 2.154
| zo | = 2.154
critical value
the value of |z | at los 10% is 1.28
we got |zo| =2.154 & | z | = 1.28
make decision
hence value of | zo | > | z | and here we reject Ho
p-value : right tail - ha : ( p > 2.154 ) = 0.016
hence value of p0.1 > 0.016, here we reject Ho
ANSWERS
---------------
null, Ho: =2.7
alternate, H1: >2.7
test statistic: 2.154
critical value: 1.28
decision: reject Ho
p-value: 0.016
we have enough evidence to support the claim

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