guided practice\nrecall the graph that shows the weights of bags of pet food distributed normally.\nthe mean…

guided practice\nrecall the graph that shows the weights of bags of pet food distributed normally.\nthe mean of the weights is 50 lb and the standard deviation is 0.2 lb.\nweight of bags\n\nuse the graph to estimate the percent of bags with weights within 1.5 standard deviations of the mean.\na. 63%\nb. 80%\nc. 77%\nd. 91%
Answer
Explanation:
Step1: Define range bounds
First, calculate the lower and upper bounds of the weight range. Lower bound: $50 - 1.5\times0.2 = 49.7$ lb Upper bound: $50 + 1.5\times0.2 = 50.3$ lb
Step2: Sum percentages in range
Add the percentages of bags with weights between 49.7 and 50.3 lb from the histogram: $8 + 10 + 18 + 16 + 8 + 5 = 65$? No, correct sum: $8 + 10 + 18 + 16 + 8 + 5 = 65$? Wait, no, check the bars: 49.7(8), 49.8(10), 49.9(18), 50.0(18? No, 50.0 is 18? Wait no, the bar for 50.0 is 18, 50.1 is 16, 50.2 is 8, 50.3 is 5. Wait no, 49.7 is 8, 49.8 is 10, 49.9 is 18, 50.0 is 18, 50.1 is 16, 50.2 is 8, 50.3 is 5. Sum: $8+10+18+18+16+8+5 = 83$? No, wait the options: the closest is 80%? No, wait the empirical rule for 1.5 standard deviations: the percentage is about 86.64%, but the histogram sum: let's add correctly: 49.7: 8%, 49.8:10%, 49.9:18%, 50.0:18%, 50.1:16%, 50.2:8%, 50.3:5% Sum: $8+10=18$, $18+18=36$, $36+18=54$, $54+16=70$, $70+8=78$, $78+5=83$. The closest option is B. 80%? Wait no, wait maybe I misread the bars. Wait 49.5:1%, 49.6:2%, 49.7:8%, 49.8:10%, 49.9:18%, 50.0:18%, 50.1:16%, 50.2:8%, 50.3:5%, 50.4:2%, 50.5:1%. The total outside 49.7-50.3 is 1+2+2+1=6%, so 100-6=94? No, no, the question is within 1.5 standard deviations, which is 49.7 to 50.3. The outside is 49.5,49.6,50.4,50.5: 1+2+2+1=6%, so 100-6=94? No, the options have 91%. Wait maybe my reading is wrong. Wait 49.7 is 7%, 49.8 is 9%, 49.9 is 17%, 50.0 is 17%, 50.1 is 15%, 50.2 is 7%, 50.3 is 4%. Sum:7+9+17+17+15+7+4=76, which is close to 77%? No. Wait the empirical rule for normal distribution: 1.5 standard deviations from mean: $P(-1.5<Z<1.5) = \Phi(1.5)-\Phi(-1.5) = 0.9332 - 0.0668 = 0.8664$, 86.64%, closest to 91%? No. Wait the histogram: let's add the bars in range: 49.7: 8, 49.8:10, 49.9:18, 50.0:18, 50.1:16, 50.2:8, 50.3:5. Total: 8+10=18, +18=36, +18=54, +16=70, +8=78, +5=83. The closest option is B. 80%? No, the options are A.63%, B.80%, C.77%, D.91%. Wait maybe I miscalculated the range: 1.5 standard deviations is 1.5*0.2=0.3, so mean 50, so 50-0.3=49.7, 50+0.3=50.3. Correct. The sum of the bars in that range is 8+10+18+18+16+8+5=83, which is closest to 80% (option B). Wait no, maybe the bar for 50.0 is 17, 49.9 is 17: 8+10+17+17+16+8+5=81, still close to 80%.
Wait no, maybe the question is to estimate from the graph, not calculate empirical rule. The sum of the bars between 49.7 and 50.3 is approximately 80%.
Answer:
B. 80%