Danielle’s chemistry professor has a complicated grading system. Each lab counts once and each test counts as two labs. At the e
nd of the semes-ter there is a fnal lab that counts as three regular labs. Danielle received scores of 84, 81, and 93 on her labs and scores of 89 and 94 on her tests. What score must she get on the fnal lab to receive an A (an A is 90)
1 answer:
Answer:
92
Step-by-step explanation:
Lab Scores are 84, 81, and 93
Test Scores are 89 and 94
Each lab counts once and each test counts as two labs. At the end of the semester there is a final lab that counts as three regular labs.
Total Number of Labs= (3X1)+(2X2)+(1X3) =3+4+3 =10
To recieve an A(90), the average of her scores must be 90.
Let her final lab score =b
Refer to the attached diagram
Total Score=624+3b
For her average =90
Cross multiplying
624+3b =90 X 10
624+3b =900
3b =900-624
3b =276
Dividing both sides by 3
b= 92
She must score 92 in her final lab to receive an A.
You might be interested in
Answer:
The upper 20% of the weighs are weights of at least X, which is , in which
is the standard deviation of all weights and
is the mean.
Step-by-step explanation:
Normal Probability Distribution:
Problems of normal distributions can be solved using the z-score formula.
In a set with mean and standard deviation
, the z-score of a measure X is given by:
The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.
Upper 20% of weights:
The upper 20% of the weighs are weighs of at least X, which is found when Z has a p-value of 0.8. So X when Z = 0.84. Then
The upper 20% of the weighs are weights of at least X, which is , in which
is the standard deviation of all weights and
is the mean.