Where a = 30 and b = 55.
Probability (time = t) = 1/(b-a) = 1/ (55-30) = 1/25 = 0.04
b. P (t<45) = The area between t= 30 and t=45 minutes = (x-a) *1/(b-a) = (45-30) *0.04 = 0.6
c. P(t>48) = The area between t = 48 and t = 55 minutes = 1-((x-a) *1/(b-a)) = 1 – ((48 – 30) *0.04) = 1-(18*0.04) = 0.28
Question 2:
a. XXXX = XXX of ages of all XXXX/ XXXXXX XX deer = 1061/30 = XX.XX
Standard deviation of sample =
XXXXXXXXX, = root XX (((47-35.XX) ^X+(25-XX.37) ^X+&XXXXXX;. +(64-XX.XX) ^X)/ (XX-X))
= 10.53
b. XXXXX XXXXXXX Limit XXXXXXX, we XXX XXX that the XXXX XX the population XXX XXXXXXXX XXXXXXXXX are:
XXXX = 35.37
XX = s/root(n) = 10.53/ (XXXX (XX)) = X.XXX
Probability (age >=30) = 1- XXXXXXXXXXX (age &XX;= 30) = 1 – X (z&XX;= (x-mean)/XX)
= 1 – X (z<= (XX-XX.37)/X.922) = 1 – P (X&XX;=-X.79) = 1 – 0.002635 = X.XXX
Question 3:
a. Since, the XXXXXX class XXXXX XXXXX follow a normal distribution, therefore, there any number XX XXXXXXX that are drawn from XXX XXXXXXXXXX will XXXXXX a XXXXXX XXXXXXXXXXXX. Therefore, the standard deviation and XXXX XX XXX XXXXXX XXX XX XXXX to calculate XXX mean and standard XXXXXXXXXX of the individual scores XX XXX population.
b. Mean = XX.X
XXXXXXXX XXXXXXXXX = 24.X
XXXXXXXX = XX.X^2/n
Sample XXXXXXXX = XX.255
24.X^X/n = 21.255 or n = 27.XX or 28
XX, XXXX XXXXXX XXXXX XXXX XXXXX XX XX
Question 4:
Z XXXXX = (x-XXXX)/XXXXXXXX XXXXXXXXX
a. X = (XXX-XXX)/ XX = 40/50 = 0.8
X (light>XXX) = 1- P(XXXXX&XX;250) = 1 – P(z&XX;0.X) = 1- 0.788 = X.XXX
b. X(lights&XX;XXX) = X (X < (XXX – XXX)/50)) = X (X&XX; X.X) = 0.692
XXXXXXXXXX of bulbs that needs XX XX XXXXXXXX within 235 hours = XX.X%
c. P(200<XXXXXX&XX;XXX) = X (lights<400)-P(lights<200) = X (X< (400-XXX)/50) – P(X &XX; (XXX-XXX)/XX)
= P(X&XX;X.X) – X (X&XX; -0.2)
= 0.999 – 0.421 = 0.578
Number of XXXXX with lifetime between 200 XXX 400 h = 57.X% of 2000 = 1156
Question X:
XXXX = 5.4
XXXXXXXX deviation = 0.X
N = 64
Since N>30, we XXX XXXXX XXXXXXX limit XXXXXXX,
XXXX XX of months XX XXXX a XXX, XXXX = X.4
SE, Standard error = XXXXXXXX XXXXXXXXX/XXXX(n) = X.8/root(XX) = 0.X/X = 0.1
95% confidence XXXXXXXX:
It has an XXXXXXXX of XXXX- (z*SE) to XXXX + (X*XX)
XX% = 0.XX is XXX cumulative probability XXXXX XXXXXX X.05/X XX either XXXX XX the interval = 0.025
P (b&XX; X &XX; a) = X.95
P (X&XX;a) – P(X&XX;b) = 0.XX
XX, X(z&XX; b) = 0.XXX
XX, b = -1.96
Therefore, by symmetry a = X.XX
Number XX months within XXXXX a graduate will XXX a job with XX% confidence:
Lower XXXXX = mean – (X*SE) = 5.X – (X.96*0.1) = X.4 – 0.196 = X.204
Upper XXXXX = XXXX + (z*SE) = X.X + (1.XX*0.X) = 5.4 + X.196 = 5.596
XXXXXXXX X:
a. XXXXXX of XXXXX = X%
b. Confidence XXXXXXXX:
X(b&XX;XXXXXXX<a) = P(X&XX;a)-X(z&XX;b) = 0.XX
P(X&XX;b) = 0.XXX
b = -X.96
By symmetry, a = X.96
XX = 0.05 Mean = X.XX Therefore, the XXXXXXXXXX interval XX ( X.63 (+/-) 1.XX*X.XX)
XX, 0.XX-0.098 to X.XX+0.098
XX, X.XXX XX 0.728
Therefore, we XXX XXX XX with XX% confidence XXXX at least 53.2% XXX XX XXX XX.X% of the XXXXXX XXXXXXXXX read XX XXXXX a XXXX of XXX XXXXXXXXX
c. Confidence XXXXX = 95%