Answer:
Step-by-step explanation:
A quadratic equation can be factorised if and only if there are rational roots.
For any quadratic equation the discriminant decides about the nature of roots.
Thus only if the discriminant is a perfect square we can have rational roots and in this case only factorization is possible.
In the given equation
Since 1 is a perfect square we can factor and solve
Why? how much points do you have to spare?
Answer:
Kindly check explanation
Step-by-step explanation:
Given that :
Mean (m) = 72
Standard deviation (sd) = 10
Grading cutoff policy:
bottom 5% receive F
next 15% receive D
next 35% receive C
next 30% receive B
A) Give the cutoffs for the grades in this course in terms of standardized scores.
Standardized score for grade cutoff:
Locating the Zscore for the proportions on the z table :
Bottom 5% = 0.05 ; corresponding Zscore = - 1.645
next 15% receive D = (5 +15)% 0.20 ; corresponding Zscore = - 0.84
next 35% receive C = (20+35)% = 0.55 ; corresponding Zscore = 0.13
next 30% receive B = (55 + 30)% = 0.85 ; Corresponding Zscore = 1.04
B) Give the cutoffs in terms of actual total scores.
Recall:
Zscore = (x - m) /sd ; where x = actual score
x = sd*z + m
For F:
10*(-1.645) + 72 = 55.55
For D:
10*(-0.84) + 72 = 63.6
For C:
10*(0.13) + 72 = 73.3
For B:
10*(1.04) + 72 = 82.4
C) Do you think that this method of assigning grades is a good one?
Yes, it is good in terms of expressing scores around the mean such that score below are negative and those above are positive. However, it is a little bit ambiguous.
