Answer:
2) (-∞, 17]
Step-by-step explanation:
The leading coefficient of the function is negative, so the parabola opens downward. The vertex will be a maximum, the upper end of the range. The lower end of the range will be -∞.
The vertex of the function lies on the axis of symmetry. The maximum can be found by evaluating the function at x=-4.
y = -(-4)² -8(-4) +1 = -16 +32 +1 = 17
The range of the function is (-∞, 17].
Answer:
a)0.6192
b)0.7422
c)0.8904
d)at least 151 sample is needed for 95% probability that sample mean falls within 8$ of the population mean.
Step-by-step explanation:
Let z(p) be the z-statistic of the probability that the mean price for a sample is within the margin of error. Then
z(p)= where
a.
z(p)= ≈ 0.8764
by looking z-table corresponding p value is 1-0.3808=0.6192
b.
z(p)= ≈ 1.1314
by looking z-table corresponding p value is 1-0.2578=0.7422
c.
z(p)= ≈ 1.6
by looking z-table corresponding p value is 1-0.1096=0.8904
d.
Minimum required sample size for 0.95 probability is
N≥ where
then N≥ ≈150.6
Thus at least 151 sample is needed for 95% probability that sample mean falls within 8$ of the population mean.