document.write( "Question 133760: Hi, Can someone help me with these 2 questions, I'm a little confused as to what I am suppose to be doing.\r
\n" ); document.write( "\n" ); document.write( "1. You are the incoming inspector for potato chips – you are to ensure that each bag has 16 ounces or more in it. You want your testing to be at the level of significance of 0.05. You pull a sample of 49 bags of chips from a recent truckload. Your sample statistics are:
\n" ); document.write( " x-bar (the sample mean) = 15.9 ounces
\n" ); document.write( " s ( the sample standard deviation) = 0.35 ounces
\n" ); document.write( "(a) what is the null and alternative hypothesis
\n" ); document.write( "(b) one or two tailed test ??
\n" ); document.write( "(c) what is the critical z value for your test at the 0.05 level of significance??
\n" ); document.write( "(d) what is the calculated z value ??
\n" ); document.write( "(e) what is your decision about the load of potato chips ??
\n" ); document.write( " -- reject ?? -- not-reject ??
\n" ); document.write( "(a) Ho : μ <= 16 Vs H1 : μ < 16 (Left tailed test)
\n" ); document.write( "(b) One tailed test
\n" ); document.write( "(c) Critical z = 1.645
\n" ); document.write( "(d) Test Statistics:
\n" ); document.write( " z = follows N(0,1)
\n" ); document.write( " = -2
\n" ); document.write( "where
\n" ); document.write( " x bar=15.9 n=49 s=0.35 μ= 16
\n" ); document.write( "(e) Rejection Rule
\n" ); document.write( "Critical Value = -1.645
\n" ); document.write( "Thus we reject H0 if z < -1.645
\n" ); document.write( "As z = -2 < -1.645 we reject H0.
\n" ); document.write( "At the 5% level of significance, the data provides enough evidence to reject the null hypothesis. Thus we conclude that each bag has less than 16 ounces.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "2. An owner of a fast food restaurant reported to corporate headquarters that the average bill paid by his customers in the last quarter was $6.20 and that the standard deviation was $1.90. Not knowing exactly what the effect would be, headquarters suddenly launched a nationwide promotional campaign featuring a large quantity discount for a multi-sandwich purchase. The stubs from the next 81 purchases at the owner’s franchise after the campaign was launched averaged $6.65.
\n" ); document.write( "
\n" ); document.write( "Conduct the 5 step hypothesis test at a level of significance of 0.05 to determine if the promotion increased the average bill amount
\n" ); document.write( "Ans.
\n" ); document.write( "• To Test
\n" ); document.write( " Ho : μ= 6.20 Vs H1 : μ > 6.20 (Right tailed test)
\n" ); document.write( "• Level of significance = 0.05
\n" ); document.write( "• Test Statistics:
\n" ); document.write( " z = xbar-μ/SE follows N(0,1)
\n" ); document.write( " = 2.13
\n" ); document.write( "where
\n" ); document.write( " xbar =6.65 n=81 sd=1.9 μ= 6.2
\n" ); document.write( "• P-value = P(z > 2.13) = 0.0165
\n" ); document.write( " Since P-value of 0.0165 < 0.05 we reject H0.
\n" ); document.write( " It is statistically significant
\n" ); document.write( "• Rejection Rule
\n" ); document.write( "Critical Value = 1.645
\n" ); document.write( "Thus we reject H0 if z > 1.645
\n" ); document.write( "As z = 2.13 > 1.645 we reject H0.
\n" ); document.write( "• Conclusion
\n" ); document.write( "At the 5% level of significance, the data provides enough evidence to reject the null hypothesis. Thus we conclude that the promotion increased the average bill amount.
\n" ); document.write( "
\n" ); document.write( "

Algebra.Com's Answer #97877 by nanaktutors@yahoo.com(8)\"\" \"About 
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1. You are the incoming inspector for potato chips – you are to ensure that each bag has 16 ounces or more in it. You want your testing to be at the level of significance of 0.05. You pull a sample of 49 bags of chips from a recent truckload. Your sample statistics are:
\n" ); document.write( " x-bar (the sample mean) = 15.9 ounces
\n" ); document.write( " s ( the sample standard deviation) = 0.35 ounces
\n" ); document.write( "(a) what is the null and alternative hypothesis
\n" ); document.write( "(b) one or two tailed test ??
\n" ); document.write( "(c) what is the critical z value for your test at the 0.05 level of significance??
\n" ); document.write( "(d) what is the calculated z value ??
\n" ); document.write( "(e) what is your decision about the load of potato chips ??
\n" ); document.write( " -- reject ?? -- not-reject ??
\n" ); document.write( "(a) Ho : μ <= 16 Vs H1 : μ < 16 (Left tailed test)
\n" ); document.write( "(b) One tailed test
\n" ); document.write( "(c) Critical z = 1.645
\n" ); document.write( "(d) Test Statistics:
\n" ); document.write( " z = follows N(0,1)
\n" ); document.write( " = -2
\n" ); document.write( "where
\n" ); document.write( " x bar=15.9 n=49 s=0.35 μ= 16
\n" ); document.write( "(e) Rejection Rule
\n" ); document.write( "Critical Value = -1.645
\n" ); document.write( "Thus we reject H0 if z < -1.645
\n" ); document.write( "As z = -2 < -1.645 we reject H0.
\n" ); document.write( "At the 5% level of significance, the data provides enough evidence to reject the null hypothesis. Thus we conclude that each bag has less than 16 ounces.\r
\n" ); document.write( "
\n" ); document.write( "\n" ); document.write( "2. An owner of a fast food restaurant reported to corporate headquarters that the average bill paid by his customers in the last quarter was $6.20 and that the standard deviation was $1.90. Not knowing exactly what the effect would be, headquarters suddenly launched a nationwide promotional campaign featuring a large quantity discount for a multi-sandwich purchase. The stubs from the next 81 purchases at the owner’s franchise after the campaign was launched averaged $6.65.
\n" ); document.write( "
\n" ); document.write( "Conduct the 5 step hypothesis test at a level of significance of 0.05 to determine if the promotion increased the average bill amount
\n" ); document.write( "Ans.
\n" ); document.write( "• To Test
\n" ); document.write( " Ho : μ= 6.20 Vs H1 : μ > 6.20 (Right tailed test)
\n" ); document.write( "• Level of significance = 0.05
\n" ); document.write( "• Test Statistics:
\n" ); document.write( " z = xbar-μ/SE follows N(0,1)
\n" ); document.write( " = 2.13
\n" ); document.write( "where
\n" ); document.write( " xbar =6.65 n=81 sd=1.9 μ= 6.2
\n" ); document.write( "• P-value = P(z > 2.13) = 0.0165
\n" ); document.write( " Since P-value of 0.0165 < 0.05 we reject H0.
\n" ); document.write( " It is statistically significant
\n" ); document.write( "• Rejection Rule
\n" ); document.write( "Critical Value = 1.645
\n" ); document.write( "Thus we reject H0 if z > 1.645
\n" ); document.write( "As z = 2.13 > 1.645 we reject H0.
\n" ); document.write( "• Conclusion
\n" ); document.write( "At the 5% level of significance, the data provides enough evidence to reject the null hypothesis. Thus we conclude that the promotion increased the average bill amount.\r
\n" ); document.write( "\n" ); document.write( "
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