A researcher is whether a vitamin has any effect on growth o

A researcher is whether a vitamin has any effect on growth of labradoodle puppies. In the general population, the weight of 2 month old labradoodles is normally distributed with an average weight of 15 pounds, with a standard deviation of 4 pounds. A sample of n = 16 puppies is obtained, and the puppies are given the vitamin supplement for 2 months. After the treatment, the average weight for the sample was 17.2 pounds. The researcher selects an alpha of .05.

Specify the null and alternative hypotheses. (1 pt.)

Specify the critical value for this test. (1 pt.)

Compute the standard error. (1 pt.)

Compute the sample z-statistic. (1 pt.)

State your decision. (1 pt.)

Compute Cohen’s d. (1 pt.)

In words, interpret Cohen’s d. (1 pt.)

Solution

Set Up Hypothesis
Null Hypothesis H0: U=25
Alternate, it has effect H1: U<25
Test Statistic
Population Mean(U)=25
Given That X(Mean)=17.2
Standard Deviation(S.D)=4
Number (n)=16
we use Test Statistic (Z) = x-U/(s.d/Sqrt(n))
Zo=17.2-25/(4/Sqrt(16)
Zo =-7.8
| Zo | =7.8
Critical Value
The Value of |Z | at LOS 0.05% is 1.64
We got |Zo| =7.8 & | Z | =1.64
Make Decision
Hence Value of | Zo | > | Z | and Here we Reject Ho
P-Value : Left Tail - Ha : ( P < -7.8 ) = 0
Hence Value of P0.05 > 0, Here we Reject Ho

vitamin has effect on growth of labradoodle puppies