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 = sum of ages XX all XXXX/ number XX deer = 1061/XX = 35.37
Standard deviation of sample =
Therefore, = root XX (((XX-35.37) ^2+(25-35.37) ^X+…. +(XX-35.XX) ^X)/ (30-X))
= XX.53
b. XXXXX XXXXXXX Limit XXXXXXX, we can XXX XXXX XXX XXXX of XXX XXXXXXXXXX XXX XXXXXXXX deviation are:
Mean = 35.XX
XX = s/root(n) = 10.53/ (XXXX (XX)) = X.XXX
Probability (age &XX;=30) = 1- XXXXXXXXXXX (age &XX;= 30) = X – P (X&XX;= (x-XXXX)/SE)
= 1 – P (z<= (30-35.37)/1.XXX) = 1 – X (z<=-X.XX) = X – 0.002635 = 0.XXX
XXXXXXXX X:
a. Since, XXX entire class XXXXX would follow a normal distribution, XXXXXXXXX, there XXX XXXXXX XX samples that are XXXXX from the XXXXXXXXXX will follow a XXXXXX XXXXXXXXXXXX. XXXXXXXXX, XXX XXXXXXXX deviation and mean XX the XXXXXX XXX be used XX XXXXXXXXX XXX mean XXX XXXXXXXX XXXXXXXXXX XX the individual XXXXXX XX XXX population.
b. XXXX = XX.7
Standard deviation = XX.3
Variance = XX.3^2/n
Sample variance = XX.255
24.X^2/n = XX.XXX or n = XX.78 or 28
So, XXXX XXXXXX XXXXX XXXX would XX 28
XXXXXXXX 4:
Z XXXXX = (x-mean)/standard XXXXXXXXX
a. X = (XXX-XXX)/ 50 = XX/XX = X.X
P (light&XX;XXX) = 1- X(XXXXX<250) = 1 – X(z<X.X) = 1- X.XXX = X.XXX
b. X(lights<235) = P (z < (XXX – 210)/XX)) = P (X&XX; 0.5) = X.XXX
Percentage of XXXXX that needs XX XX replaced XXXXXX 235 XXXXX = XX.2%
c. X(XXX<XXXXXX<XXX) = P (lights&XX;400)-P(XXXXXX&XX;200) = X (z< (400-210)/50) – P(X &XX; (XXX-XXX)/XX)
= X(X&XX;3.X) – P (z&XX; -X.X)
= 0.999 – 0.XXX = X.578
XXXXXX XX XXXXX XXXX XXXXXXXX between XXX and 400 h = 57.X% of 2000 = 1156
Question X:
XXXX = 5.X
Standard XXXXXXXXX = 0.8
N = XX
Since N>XX, we can apply XXXXXXX limit XXXXXXX,
Mean no of XXXXXX XX XXXX a XXX, XXXX = X.X
XX, Standard XXXXX = standard XXXXXXXXX/root(n) = X.8/XXXX(64) = 0.8/X = X.X
95% confidence interval:
It XXX an interval XX XXXX- (X*XX) to mean + (z*XX)
XX% = 0.95 XX the XXXXXXXXXX probability XXXXX XXXXXX X.XX/X XX either XXXX XX the XXXXXXXX = 0.025
X (b&XX; z < a) = X.95
X (X<a) – X(X<b) = X.XX
Or, P(X&XX; b) = X.025
XX, b = -X.XX
XXXXXXXXX, by symmetry a = 1.96
XXXXXX of XXXXXX within which a XXXXXXXX XXXX get a job with XX% XXXXXXXXXX:
Lower limit = XXXX – (X*SE) = 5.X – (1.XX*0.X) = 5.X – X.XXX = X.204
XXXXX XXXXX = XXXX + (X*XX) = X.X + (X.96*0.X) = X.X + 0.XXX = 5.596
a. Margin XX XXXXX = X%
b. XXXXXXXXXX XXXXXXXX:
P(b&XX;readers<a) = P(z<a)-X(X&XX;b) = X.95
X(X<b) = 0.XXX
b = -X.96
XX XXXXXXXX, a = 1.96
XX = X.XX XXXX = X.63 XXXXXXXXX, the confidence interval is ( X.XX (+/-) 1.96*X.05)
Or, 0.XX-0.098 XX X.XX+0.XXX
XX, X.XXX XX X.XXX
XXXXXXXXX, XX XXX say XX XXXX XX% confidence that XX least 53.X% XXX at max 72.8% of the XXXXXX regularly read at least a part of XXX XXXXXXXXX
c. XXXXXXXXXX level = 95%