Statistics 101 problem. Using confidence values and z scores?

  • Thread starter Thread starter famtrecrew
  • Start date Start date
  • Tags Tags
    Statistics
AI Thread Summary
A study examined whether zinc supplementation during pregnancy increases birth weight, using a significance level of 0.05. The zinc group had a sample size of 294 with an average weight of 3214 grams, while the placebo group had 286 participants with an average weight of 3088 grams. The initial calculations involved using z-scores, but there was confusion regarding hypothesis testing and the correct formula. The calculated z-score of 3.229 exceeded the critical value of 1.96, suggesting a rejection of the null hypothesis, indicating a positive effect of zinc on weight gain. However, it was noted that due to differing standard deviations and sample sizes, a pooled standard deviation should be used for more accurate results.
famtrecrew
Messages
5
Reaction score
0
1. A study of zinc-deficient mothers was conducted to determine whether zinc supplemnetation during pregnancy results in babies with increased weight at birth. The weights are measured in grams. Use a 0.05 significance level to test the claim that zinc supplementation does increase weight at birth



2. Zinc group: n=294 xbar=3214 s=669

Placebo Group: n=286 xbar=3088 s=728




3. I tried using z scores to figure this out by using the equation z= xbar-m/sigma/[squareroot of n] however i am not sure if i need some sort of hypothesis testing or how to go about solving this. Since i don't know m I was using the xbar1-xbar2 on the numerator. Any help is appreciated. The answer i got was using Hnot: m<=0 and H1: m>0. Then getting 1.96 and a calculated z score of 3.229. Since 3.229>1.96 I stated that we reject Hnot and which means that m is greater than 0 showing a positive weight gain in the zinc supliment category. I think that this is wrong though.
 
Physics news on Phys.org
I picked up this problem from the Schaum's series book titled "College Mathematics" by Ayres/Schmidt. It is a solved problem in the book. But what surprised me was that the solution to this problem was given in one line without any explanation. I could, therefore, not understand how the given one-line solution was reached. The one-line solution in the book says: The equation is ##x \cos{\omega} +y \sin{\omega} - 5 = 0##, ##\omega## being the parameter. From my side, the only thing I could...
Back
Top