7. (10 pts) An engineer wants to measure the bias in a pH meter. She uses the me

Question

7. (10 pts) An engineer wants to measure the bias in a pH meter. She uses the meter to measure the pH in 14 neutral substances (pH=7.0) and obtains the data shown in the table 7.01 7.04 6.97 7.00 6.99 6.97 7.04 7.04 7.0 7.00 6.99 7.04 7.07 6.97 Is there evidence to support that the pH meter is correctly calibrated? Use the = 0.05 level of significance 8. (10 pts) The student body at many community colleges is considered a "commuter population". The following question was asked of the student affairs office at one such college; How far does the average community college student commute to college daily? The answer was no more than 9 mi. The inquirer was not convinced and decided to test the statement. She took a random sample of 20 students and found a mean community distance of 10.22 mi with the sample standard deviation 5 mi. State and test the hypothesis as a significance level of = 0.05 9. (10 pts) Salt-free diets are often prescribed to people with high blood pressure. The following data values were obtained from an experiment designed to estimate the reduction in diastolic blood pres- sure as a result of consuming a salt-free diet for 2 weeks. Assume diastolic readings to be normally distributed BCD EFGH Patients Before 93 106 8792 102 9588 110 After 921028992 101 9688 105 (a) Calculate a 90% confidence interval for the mean reduction (b) Is there evidence that diastolic blood pressure is reduced by having salt-free diets, use = 0.05

Explanation / Answer

Q7.

Given that,
population mean(u)=7
sample mean, x =7.01
standard deviation, s =0.0316
number (n)=14
null, Ho: =7
alternate, H1: !=7
level of significance, = 0.05
from standard normal table, two tailed t /2 =2.16
since our test is two-tailed
reject Ho, if to < -2.16 OR if to > 2.16
we use test statistic (t) = x-u/(s.d/sqrt(n))
to =7.01-7/(0.0316/sqrt(14))
to =1.1841
| to | =1.1841
critical value
the value of |t | with n-1 = 13 d.f is 2.16
we got |to| =1.1841 & | t | =2.16
make decision
hence value of |to | < | t | and here we do not reject Ho
p-value :two tailed ( double the one tail ) - Ha : ( p != 1.1841 ) = 0.2576
hence value of p0.05 < 0.2576,here we do not reject Ho
ANSWERS
---------------
null, Ho: =7
alternate, H1: !=7
test statistic: 1.1841
critical value: -2.16 , 2.16
decision: do not reject Ho
p-value: 0.2576

we have evidence that it is correctly uptained

Related Questions

Navigate

• Browse (All)
• Browse 7
• Subjects

---

---

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.