if the mean is 70 minutes, then 90 minutes is 2 standard deviations above 70. if you look at the bell curve i drew, the percent of exams that took over 90 minutes is 2.5%
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1+2=3. 4/10+2/10=6/10. 3+ 6/10=3 6/10
Answer: This sample may be biased because he is only asking the bike riders when in reality there might be a majority of students who instead take an alternate form of transportation
Step-by-step explanation:
69 out of 100 would be 69/100 = 0.69 = 69% were answered correctly
100% - 69% = 100-69 = 31 = 31% = 31/100 were incorrect
