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Students taking a standardized iq test had a mean score of 100 with a standard deviation of 15. assume that the scores are norma

Lera25 [3.4K]

The standardized probability of a normally distributed data is given by
P(X < x) = P(z < (x - mean) / standard deviation)
P(X > x) = 1 - P(X < x)
P(X > 125) = 1 - P(X < 125) = 1 - P(z < (125 - 100) / 15) = 1 - P(z < 25/15) = 1 - P(z < 1.667) = 1 - 0.95221 = 0.04779 = 4.8%

Though it cannot be said to be usual, at the same time it is not unusual because 125 is above the first standard deviation of the mean but below the second standard deviation of the mean.

5 0

3 years ago

Use angle difference identity to find the exact value.

Otrada [13]

Hello,

1)
tan (a-b)=(tan a - tan b)/(1+tan a tan b)

15=45-30
tan 45°= (√2/2)/(√2/2)=1
tan 30°=(1/2)/(√3/2)=√3/3
tan (45°-30°)= (1-√3/3)/(1+1*√3/3)=(3-√3)/(3+√3)=(3-√3)²/6=2-√3

tan (-105°)=tan (75°)= tan (60°+15°)=(tan 60+tan15°)/(1-tan 60°*tan 15°)

tan 15°=2-√3
tan 60°=√3°
tan (-105°)=(√3+2-√3)/(1-√3*(2-√3))=2/(1-2√3+3)=1/(2-√3)=2+√3

8 0

3 years ago

Factor x2 + 11x + 30.

andrey2020 [161]

Answer:

(x +5)(x +6)

Step-by-step explanation:

You're looking for two factors of 30 that total 11.

30 = 1×30 = 2×15 = 3×10 = 5×6

5+6 = 11, so those are the numbers you want in the binomial factors.

x^2 +11x +30 = (x +5)(x +6)

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