Question

According to a 2005 Harris Interactive/HealthDay poll, 74% of American adults, age 18 years and older, supported the use of embryonic stem cells in medical research. During a September 28-30, 2010 Harris Interactive/HealthDay poll conducted online within the United States, participants were asked to read and consider the statement below.

"Stem cells come from embryos, left over from in vitro fertilization, which are not used and normally destroyed. Many medical researchers want to use them to develop treatments or to prevent diseases such as diabetes, Alzheimer's or Parkinson's disease. On balance, do you think this research should be allowed or not be allowed?"

Among the 2,113 adults, age 18 years and older, surveyed, 72% responded* that medical research using embryonic stem cells should be allowed. Based on this survey, you believe that the percentage of adults in the United States who support medical research using embryonic stem cells has decreased.

Determine the test statistic.

Determine if there is sufficient evidence at a 0.01 level of significance for you to conclude that the percentage of adults in the United States who support medical research using embryonic stem cells has decreased using both the classical approach and the p-value approach. State your conclusion in the context of this scenario.

• Classical Approach:

• p-Value Approach:

• In-context Conclusion:

Answer 1

Answer)

Ho : p = 0.74

Ha : p < 0.74

Given n = 2113

Observed p = 0.72

As the sample size is large, we can use standard normal z table to conduct the test

Test statistics z = (observed p - claimed p)/standard error

Standard error = √claimed p*(1-claimed p)/√n

Observed p = 0.72

Claimed p = 0.74

N = 2113

Z = -2.1

From z table, p(z<-2.1) = 0.0179

As the obtained p-value is greater than 0.01

We fail to reject Ho

And we do not have enough evidence to support the claim that, p is less than 0.74

Classical approach

From z table, p(z<-2.33) = 0.01

That is critical value is -2.33

And rejection region is if z <-2.33

But our z is = -2.1 which is not less than -2.33

So, we fail to reject Ho