A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.02 with 95% confidence if (a) she uses a previous estimate of 0.42? (b) she does not use any prior estimates?
(a)Solution :
Given that,
= 0.42
1 - = 1 - 0.42 = 0.58
margin of error = E = 0.02
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2 = Z0.025 = 1.96
Sample size = n = (Z/2 / E)2 * * (1 - )
= (1.96/ 0.02)2 * 0.42 * 0.58
= 2339.53 = 2340
Sample size = 2340
(b) Solution :
Given that,
= 0.5 (when estimate is not given then 0.5)
1 - = 1 - 0.5 = 0.5
margin of error = E = 0.02
At 95% confidence level the z is ,
= 1 - 95% = 1 - 0.95 = 0.05
/ 2 = 0.05 / 2 = 0.025
Z/2 = Z0.025 = 1.96
Sample size = n = (Z/2 / E)2 * * (1 - )
= (1.96/ 0.02)2 * 0.5 * 0.5
= 2401
Sample size = 2401
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size...
A researcher wishes to estimate the proportion of adults who have high-speed internet access. What size sample should be obtained if she wishes to estimate to be within 0.02 with 95% confidence if (a) She uses a previous estimate of 0.38? (b) she does not use any prior estimates?
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.03 with 95% confidence if (a) she uses a previous estimate of 0.34? (b) she does not use any prior estimates? (Round up to the nearest integer).
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.02 with 99% confidence if (a) she uses a previous estimate of 0.58? (b) she does not use any prior estimates? Click the icon to view the table of critical values (a) n (Round up to the nearest Integer)
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.03 with 90% confidence if (a) she uses a previous estimate of 0.58? (b) she does not use any prior estimates?
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.05 with 99% confidence if (a) she uses a previous estimate of 0.48? (b) she does not use any prior estimates?
A researcher wishes to estimate the proportion of adults who have high-speed internet access. What size sample should be obtained if she wishes the estimate to be within .05 with 90% confidence if A. She uses a previous estimate of .48? B. She does not use any prior estimates?
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.050.05 with 9090% confidence if a) she uses a previous estimate of 0.36? b) she does not use any prior estimates?
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.02 with 90% confidence if a) she uses a previous estimate of 0.34? b) she does not use any prior estimates? a) nequals nothing (Round up to the nearest integer.) b) nequals nothing (Round up to the nearest integer.)
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.05 with 99% confidence if (a) she uses a previous estimate of 0.58? (b) she does not use any prior estimates? (Round up to the nearest integer).
A researcher wishes to estimate the proportion of adults who have high-speed Internet access. What size sample should be obtained if she wishes the estimate to be within 0.010.01 with 9090% confidence if (a) she uses a previous estimate of 0.520.52? (b) she does not use any prior estimates? (a) nequals=?(Round up to the nearest integer.)