4.
The Indigo Insurance Company is a large company based in Melbourne. Several years ago, an email survey of all their
...
survey of all their employees found that employees were required to respond to an average of 50 work-related emails per week with a standard deviation of 1.5 emails per week. However, an employee advocacy group believes the average number of work-related emails Indigo Insurance Company employees are now required to respond to is more than 50 emails per week.
To investigate this further, the employee advocacy group took a random sample of 20 staff employed by Indigo Insurance Company during the second week of March 2018,and asked these employees to record the number of work-related emails to which they were required to respond.
(b). What does the highlighted section of the distribution in Figure 1 represent?
(c). The random sample of 20 employees of Indigo Insurance Company taken by the employee advocacy group turned out to have a mean of 50.8 work-related emails to respond to in that week. Does this sample look like it belongs to the sampling distribution displayed in Figure 1? Justify your answer.
(d). Given the sample was randomly selected and that the number of work-related emails each employee was required to respond to was recorded accurately, what conclusion can we reach from part (c)?
To answer questions (b) to (d), consider the sampling distribution shown in Figure 1.
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5.A uniform beam of length L
and mass m shown in Figure
P12.16 is inclined at an angle
u to the horizontal. Its
...
izontal. Its upper
end is connected to a wall by
a rope, and its lower end rests
on a rough, horizontal sur-
face. The coefficient of static
friction between the beam
and surface is ms. Assume
the angle u is such that the static friction force is at its
maximum value. (a) Draw a force diagram for the beam.
(b) Using the condition of rotational equilibrium,
find an expression for the tension T in the rope in
terms of m, g, and u. (c) Using the condition of trans-
lational equilibrium, find a second expression for T in
terms of ms, m, and g. (d) Using the results from parts
(a) through (c), obtain an expression for ms
L
u
Figure P12.16
Q/C
S
vertical component of this force. Now solve the same
problem from the force diagram from part (a) by com-
puting torques around the junction between the cable
and the beam at the right-hand end of the beam. Find
(e) the vertical component of the force exerted by the
pole on the beam, (f) the tension in the cable, and
(g) the horizontal component of the force exerted
by the pole on the beam. (h) Compare the solution
to parts (b) through (d) with the solution to parts
(e) through (g). Is either solution more accurate?
19. Sir Lost-a-Lot dons his armor and sets out from the
castle on his trusty steed (Fig. P12.19). Usually, the
drawbridge is lowered to a horizontal position so that
the end of the bridge rests on the stone ledge. Unfor-
tunately, Lost-a-Lot’s
squire didn’t lower the draw-
involv-
ing only the angle u. (e) What happens if the ladder
is lifted upward and its base is placed back on the
ground slightly to the left of its position in Figure
P12.16? Explain.
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