標題:
發問:
When do children in the UK develop preferences for brand-name products? In a recent study, marketers showed children identical pictures of athletic shoes. One picture was labeled FW, and one was labeled Run. The children were asked to evaluate the shoes based on their appearancen, quality, price, prestige,... 顯示更多 When do children in the UK develop preferences for brand-name products? In a recent study, marketers showed children identical pictures of athletic shoes. One picture was labeled FW, and one was labeled Run. The children were asked to evaluate the shoes based on their appearancen, quality, price, prestige, favorableness, and preference for owning. A score from 2 (highest product evaluation possible) to -2 (lowest product evaluation possible) was recorded for each child. The following table reports the results of the study: Age 8: a) FW: Sample Size 28 / Sample Mean: 0.87 / Sample Standard Deviation: 0.97 b) Run: Sample Size 21/ Sample Mean: 0.85 / Sample Standard Deviation: 1.04 Age12: a) FW: Sample size: 42/ SMean: 0.89/ SD: 1.04 b) Run: SSize: 44/ Smean: 0.09/ SD: 1.07 Age 16: a) FW: SSize: 38/ SMean: 0.48/ SD: 0.82 b) Run: SSize: 35/ SMean: -0.30 / SD:0.93 Q1: Conduct a pooled-variance t test for the difference between the two means for each of the three age groups. Use a level of sign. of 0.05 Q2: Wht assumptions are needed to conduct the tests in Q1? Q3: Write a brief summary of your findings
最佳解答:
Q1. Age 8: s = √{[(n1-1)*s1^2+(n2-1)*s2^2]/(n1+n2-2)} = √{[(28-1)*(0.97)^2+(21-1)*(1.04)^2]/(28+21-2)} = √(47.0363/47) = √(1.0008) = 1.0004 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = [(X1_bar-X2_bar)-(μ1-μ2)]/[s*√(1/n1+1/n2)] = (0.87-0.85)/[1.0004*√(1/28+1/21)] = 0.02/0.289 = 0.07 Since the t-statistic is small, we do NOT reject H0. (p-value > 0.05) Age 12: s = √{[(42-1)*(1.04)^2+(44-1)*(1.07)^2]/(42+44-2)} = √(93.5763/84) = √(1.114) = 1.06 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = (0.89-0.09)/[1.06*√(1/42+1/44)] = 0.8/0.228 = 3.51 Since the t-statistic is large, we reject H0. (p-value < 0.01) Age 16: s = √{[(38-1)*(0.82)^2+(35-1)*(0.93)^2]/(38+35-2)} = √(54.2854/71) = √(0.7646) = 0.8744 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = (0.48+0.30)/[0.8744*√(1/38+1/35)] = 0.78/0.205 = 3.81 Since the t-statistic is large, we reject H0. (p-value < 0.01) Q2. Assumption: 2 populations originally are normally distributed. population variances are equal.(less important) Q3. We notice that the difference in sample mean for age 8 group is only 0.02 but at least 0.7 for the other 2 groups. Therefore, we can conclude that there is NO difference between the two means for age 8 children. However, the two means start to be different as we increase the age of a particular group.
其他解答:
我做文職, 133磅, 用咗簡單經濟既方法!減左22磅,改善頭痛,胃痛,暈車浪, 靜脈曲脹 我個女14歲由小到大肥胖, 三個月減20磅.改善鼻敏感, 流鼻血, 讀書仲好咗, 仲拿第一添. 腸胃健康 營養蛋白素 一杯營養代餐相當於33種蔬菜, 6種水果,內含200多種營養素, 蛋白素相等於5錢燕窩、2份蔬菜、1份水果、1塊牛扒同半杯鮮奶！ 濃縮蘆薈汁 功能 : 促進體內的自我潔淨功能，令消化系統更健康 紓緩消化系統壓力 維護消化系統功能正常運作，確保腸胃的潔淨 清除體內毒素。 增強免疫功能。 對抗炎症，消炎止痛。 促進傷口愈合。 健康新文化www.HealthComeTrue.com/life
此文章來自奇摩知識+如有不便請留言告知
Stat. Question: Sample T test發問:
When do children in the UK develop preferences for brand-name products? In a recent study, marketers showed children identical pictures of athletic shoes. One picture was labeled FW, and one was labeled Run. The children were asked to evaluate the shoes based on their appearancen, quality, price, prestige,... 顯示更多 When do children in the UK develop preferences for brand-name products? In a recent study, marketers showed children identical pictures of athletic shoes. One picture was labeled FW, and one was labeled Run. The children were asked to evaluate the shoes based on their appearancen, quality, price, prestige, favorableness, and preference for owning. A score from 2 (highest product evaluation possible) to -2 (lowest product evaluation possible) was recorded for each child. The following table reports the results of the study: Age 8: a) FW: Sample Size 28 / Sample Mean: 0.87 / Sample Standard Deviation: 0.97 b) Run: Sample Size 21/ Sample Mean: 0.85 / Sample Standard Deviation: 1.04 Age12: a) FW: Sample size: 42/ SMean: 0.89/ SD: 1.04 b) Run: SSize: 44/ Smean: 0.09/ SD: 1.07 Age 16: a) FW: SSize: 38/ SMean: 0.48/ SD: 0.82 b) Run: SSize: 35/ SMean: -0.30 / SD:0.93 Q1: Conduct a pooled-variance t test for the difference between the two means for each of the three age groups. Use a level of sign. of 0.05 Q2: Wht assumptions are needed to conduct the tests in Q1? Q3: Write a brief summary of your findings
最佳解答:
Q1. Age 8: s = √{[(n1-1)*s1^2+(n2-1)*s2^2]/(n1+n2-2)} = √{[(28-1)*(0.97)^2+(21-1)*(1.04)^2]/(28+21-2)} = √(47.0363/47) = √(1.0008) = 1.0004 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = [(X1_bar-X2_bar)-(μ1-μ2)]/[s*√(1/n1+1/n2)] = (0.87-0.85)/[1.0004*√(1/28+1/21)] = 0.02/0.289 = 0.07 Since the t-statistic is small, we do NOT reject H0. (p-value > 0.05) Age 12: s = √{[(42-1)*(1.04)^2+(44-1)*(1.07)^2]/(42+44-2)} = √(93.5763/84) = √(1.114) = 1.06 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = (0.89-0.09)/[1.06*√(1/42+1/44)] = 0.8/0.228 = 3.51 Since the t-statistic is large, we reject H0. (p-value < 0.01) Age 16: s = √{[(38-1)*(0.82)^2+(35-1)*(0.93)^2]/(38+35-2)} = √(54.2854/71) = √(0.7646) = 0.8744 H0: μ1-μ2 = 0 H1: μ1-μ2 not = 0 t = (0.48+0.30)/[0.8744*√(1/38+1/35)] = 0.78/0.205 = 3.81 Since the t-statistic is large, we reject H0. (p-value < 0.01) Q2. Assumption: 2 populations originally are normally distributed. population variances are equal.(less important) Q3. We notice that the difference in sample mean for age 8 group is only 0.02 but at least 0.7 for the other 2 groups. Therefore, we can conclude that there is NO difference between the two means for age 8 children. However, the two means start to be different as we increase the age of a particular group.
其他解答:
我做文職, 133磅, 用咗簡單經濟既方法!減左22磅,改善頭痛,胃痛,暈車浪, 靜脈曲脹 我個女14歲由小到大肥胖, 三個月減20磅.改善鼻敏感, 流鼻血, 讀書仲好咗, 仲拿第一添. 腸胃健康 營養蛋白素 一杯營養代餐相當於33種蔬菜, 6種水果,內含200多種營養素, 蛋白素相等於5錢燕窩、2份蔬菜、1份水果、1塊牛扒同半杯鮮奶！ 濃縮蘆薈汁 功能 : 促進體內的自我潔淨功能，令消化系統更健康 紓緩消化系統壓力 維護消化系統功能正常運作，確保腸胃的潔淨 清除體內毒素。 增強免疫功能。 對抗炎症，消炎止痛。 促進傷口愈合。 健康新文化www.HealthComeTrue.com/life
文章標籤
全站熱搜
留言列表
