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Unformatted text preview: So the answer to the problem is Yes. Problem 7 The Mars Candy Co. claims that since the introduction of blue as a color for M&M’s 15% of all M&M’s produced are blue. In a randomly collected sample of 80 M&M’s, only 8 were blue. Is this strong evidence at 5% level to claim that the true proportion of all M&M’s that are blue is less than 15%? Tick the correct answer: q༇ Yes q༇ No q༇ Don’t have suf_icient data to conduct a correct statistical test H A : p < 0.15
Step 1: write the alternative hypothesis correctly and recognize that it’s a 1 sided less than alternative. Step2: recognize that it will be a z test for proportion Step 3: check if conditions for the tests are met. If yes proceed with the tests else choose ‘need more data’ option. np0 = 80*0.15=12 and n(1 p0)=80*0.85=68. So we are good J༄ Step 4: Critical value at 5% level=  1.645 (from normal table values). Calculate: z= ˆ
p − p0
=
p0 (1 − p0 )
n 8 / 80 − 0.15
= −1.252
0.15(1 − 0.15)
80 Step5: Fail to null...
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 Fall '07
 Lv

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