1. You are part of a research team investigation the impact of Free Senior High School of education policy on teenage pregnancy in some selected deprived district assemblies in Ghana. Team wishes to obtain an appropriate sample size to ensure reliability of the study. The team has adopted sample size formula as follows: n= Where n= sample size; Z is the critical value; o is the standard deviation of the outcome variable and E is the desired margin of error. Required: a) Discussed what happens to the sample size under the following situations: i) ii) iii) b) Assuming that you calculate the sample size using the formula adopted by the team and you obtained 300 samples. The team lead however suggest that you increase the sample size to 600. Explain the effect of the decision on the reliability of the research result. 2. A researcher wants to estimate the proportion of female students at University of Freedom who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen should be involved in the study to ensure that a 95% confidence interval estimate of the proportion of freshmen who smoke is within 5% of the true proportion? E increases, all other parameter remains constant o reduces with all other parameters' constant Confidence level changes from 95% to 99%. Use the formula: n=p|1-p|: Where n is the sample size; p Z is the value from the standard normal distribution reflecting the confidence level that will be used (e.g., Z=1.96 for 95%) and E is the desired margin of error. p is the proportion of successes in the population (assume 50%). (Answer 384) 3. A researcher wants to estimate the impact of alcohol during pregnancy on premature delivery. Normal pregnancies last approximately 40 weeks and premature deliveries are those that occur before 37 weeks. The 2020 Statistics report indicates that approximately 12% of infants are born prematurely in the Ghana The researcher plans to collect data through medical record review and to generate a 95% confidence interval for the difference in proportions of infants born prematurely to women who smoked during pregnancy as compared to those who did not. How many women should be enrolled in the study to ensure that the 95% confidence interval for the difference in proportions has a margin of error of no more than 4%? = {P1(1-P1) +P2(1– P2)}( Hint, use:

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  1. You are part of a research team investigation the impact of Free Senior High School of education policy on teenage pregnancy in some selected deprived district assemblies in Ghana. Team wishes to obtain an appropriate sample size to ensure reliability of the study. The team has adopted sample size formula as follows:

                                

Where n= sample size; Z is the critical value; σ is the standard deviation of the outcome variable and E is the desired margin of error.

 

Required:

  1. Discussed what happens to the sample size under the following situations:
  2. E increases, all other parameter remains constant
  3. σ reduces with all other parameters’ constant
  • Confidence level changes from 95% to 99%.
  1. Assuming that you calculate the sample size using the formula adopted by the team and you obtained 300 samples. The team lead however suggest that you increase the sample size to 600. Explain the effect of the decision on the reliability of the research result.
  2. A researcher wants to estimate the proportion of female students at University of Freedom who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen should be involved in the study to ensure that a 95% confidence interval estimate of the proportion of freshmen who smoke is within 5% of the true proportion?

Use the formula:

                                                  

Where n is the sample size; p  Z is the value from the standard normal distribution reflecting the confidence level that will be used (e.g., Z = 1.96 for 95%) and E is the desired margin of error. p is the proportion of successes in the population (assume 50%). (Answer 384)

1. You are part of a research team investigation the impact of Free Senior High School of
education policy on teenage pregnancy in some selected deprived district assemblies in
Ghana. Team wishes to obtain an appropriate sample size to ensure reliability of the study.
The team has adopted sample size formula as follows:
Zo
E
Where n= sample size; Z is the critical value; o is the standard deviation of the outcome
variable and E is the desired margin of error.
Required:
a) Discussed what happens to the sample size under the following situations:
i)
ii)
iii)
b) Assuming that you calculate the sample size using the formula adopted by the team and
you obtained 300 samples. The team lead however suggest that you increase the sample
size to 600. Explain the effect of the decision on the reliability of the research result.
2. A researcher wants to estimate the proportion of female students at University of Freedom
who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen
should be involved in the study to ensure that a 95% confidence interval estimate of the
proportion of freshmen who smoke is within 5% of the true proportion?
Use the formula:
E increases, all other parameter remains constant
o reduces with all other parameters' constant
Confidence level changes from 95% to 99%.
2
n=p|1- p
Where n is the sample size; p Z is the value from the standard normal distribution reflecting
the confidence level that will be used (e.g., Z=1.96 for 95%) and E is the desired margin of
error. p is the proportion of successes in the population (assume 50%). (Answer 384)
3. A researcher wants to estimate the impact of alcohol during pregnancy on premature
delivery. Normal pregnancies last approximately 40 weeks and premature deliveries are
those that occur before 37 weeks. The 2020 Statistics report indicates that approximately
12% of infants are born prematurely in the Ghana The researcher plans to collect data
through medical record review and to generate a 95% confidence interval for the difference
in proportions of infants born prematurely to women who smoked during pregnancy as
compared to those who did not. How many women should be enrolled in the study to ensure
that the 95% confidence interval for the difference in proportions has a margin of error of
no more than 4%?
= {P1(1-P1)+ P2(1– P2)}(
Hint, use:
n; is the sample size required in each group (i=1,2), Z is the value from the standard normal
distribution reflecting the confidence level that will be used (e.g., Z = 1.96 for 95%), and E
is the desired margin of error. p1 and p2 are the proportions of successes in each comparison
group. (Answer 507.1 = 508 pregnant women).
4. A team of researchers are carrying out a research project with of aim of finding out whether
Ghanaian Children are watching too much of Television in recent times. In developing the
research hypothesis, each of the three members of the research team proposes a claim for
the study:
John's Claim: Ghanaian Children spend 6 hours every day to watch television.
Joshua's Claim: Ghanaian Children spend more than 6 hours every day to watch television.
Jones' Claim: Ghanaian Children spend less than 6 hours every day to watch television.
Required:
i)
Formulate the hypothesis separately for each of the claims of the research teach
members.
ii)
iii)
Indicate whether each hypothesis require a one-tail test of two tail test and explain.
Assume that the null hypothesis of John is true in the population but the sample test
revealed a p-value of 0.080 at 5% significance. Explain if an error is committed, and
if yes explain the type of error and how it can be remedied.
Assume the t-test statistic relating to the Joshua's hypothesis is 2.921 at 5% level of
significance, what conclusion would you draw for the study.
Assume the p-value of 0.101 was found for Jones hypothesis, write the conclusion
of the study given significance of level of 0.05.
iv)
v)
Transcribed Image Text:1. You are part of a research team investigation the impact of Free Senior High School of education policy on teenage pregnancy in some selected deprived district assemblies in Ghana. Team wishes to obtain an appropriate sample size to ensure reliability of the study. The team has adopted sample size formula as follows: Zo E Where n= sample size; Z is the critical value; o is the standard deviation of the outcome variable and E is the desired margin of error. Required: a) Discussed what happens to the sample size under the following situations: i) ii) iii) b) Assuming that you calculate the sample size using the formula adopted by the team and you obtained 300 samples. The team lead however suggest that you increase the sample size to 600. Explain the effect of the decision on the reliability of the research result. 2. A researcher wants to estimate the proportion of female students at University of Freedom who currently smoke cigarettes (i.e., the prevalence of smoking). How many freshmen should be involved in the study to ensure that a 95% confidence interval estimate of the proportion of freshmen who smoke is within 5% of the true proportion? Use the formula: E increases, all other parameter remains constant o reduces with all other parameters' constant Confidence level changes from 95% to 99%. 2 n=p|1- p Where n is the sample size; p Z is the value from the standard normal distribution reflecting the confidence level that will be used (e.g., Z=1.96 for 95%) and E is the desired margin of error. p is the proportion of successes in the population (assume 50%). (Answer 384) 3. A researcher wants to estimate the impact of alcohol during pregnancy on premature delivery. Normal pregnancies last approximately 40 weeks and premature deliveries are those that occur before 37 weeks. The 2020 Statistics report indicates that approximately 12% of infants are born prematurely in the Ghana The researcher plans to collect data through medical record review and to generate a 95% confidence interval for the difference in proportions of infants born prematurely to women who smoked during pregnancy as compared to those who did not. How many women should be enrolled in the study to ensure that the 95% confidence interval for the difference in proportions has a margin of error of no more than 4%? = {P1(1-P1)+ P2(1– P2)}( Hint, use: n; is the sample size required in each group (i=1,2), Z is the value from the standard normal distribution reflecting the confidence level that will be used (e.g., Z = 1.96 for 95%), and E is the desired margin of error. p1 and p2 are the proportions of successes in each comparison group. (Answer 507.1 = 508 pregnant women). 4. A team of researchers are carrying out a research project with of aim of finding out whether Ghanaian Children are watching too much of Television in recent times. In developing the research hypothesis, each of the three members of the research team proposes a claim for the study: John's Claim: Ghanaian Children spend 6 hours every day to watch television. Joshua's Claim: Ghanaian Children spend more than 6 hours every day to watch television. Jones' Claim: Ghanaian Children spend less than 6 hours every day to watch television. Required: i) Formulate the hypothesis separately for each of the claims of the research teach members. ii) iii) Indicate whether each hypothesis require a one-tail test of two tail test and explain. Assume that the null hypothesis of John is true in the population but the sample test revealed a p-value of 0.080 at 5% significance. Explain if an error is committed, and if yes explain the type of error and how it can be remedied. Assume the t-test statistic relating to the Joshua's hypothesis is 2.921 at 5% level of significance, what conclusion would you draw for the study. Assume the p-value of 0.101 was found for Jones hypothesis, write the conclusion of the study given significance of level of 0.05. iv) v)
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