If shear-strength measurements have a standard deviation
of 10 psi, how_many test welds should be used...
If shear-strength measurements have a standard deviation
of 10 psi, how_many test welds should be used in the sample if the
sample mean is to be within 1 psi of the population mean with
probability approximately 0.95?
The shear strength of each of ten test spot welds is determined, yielding the following data (psi).
389
405
409
367
358
415
376
375
367
362
(a) Assuming that shear strength is normally distributed, estimate the true average shear strength and standard deviation of shear strength using the method of maximum likelihood. (Round your answers to two decimal places.)
average
382.3 psi
standard deviation
20.8 psi
(b) Again assuming...
The shear strength of each of ten test spot welds is determined,
yielding the following data (psi).
381
358
367
409
375
415
362
361
367
389
(a) Assuming that shear strength is normally distributed,
estimate the true average shear strength and standard deviation of
shear strength using the method of maximum likelihood. (Round your
answers to two decimal places.)
(b) Again assuming a normal distribution, estimate the strength
value below which 95% of all welds will have their strengths....
The shear strength of each of ten test spot welds is determined,
yielding the following data (psi).
362
375
389
415
358
409
379
380
367
366
(a) Assuming that shear strength is normally distributed,
estimate the true average shear strength and standard deviation of
shear strength using the method of maximum likelihood. (Round your
answers to two decimal places.)
average
psi
standard deviation
psi
(b) Again assuming a normal distribution, estimate the strength
value below which 95% of...
Compute the range and sample standard deviation for strength of
the concrete (in psi).
3910,4080,3300,3100,2940,3870,4082,4040.
The range is ___ psi
s= ___ psi (Round to one decimal place as needed).
An article considered regressing y = 28-day
standard-cured strength (psi) against x =
accelerated strength (psi). Suppose the equation of the true
regression line is y = 1900 +
1.4x,
and that the standard deviation of the random deviation
ϵ is 350 psi.
(a)
What is the probability that the observed value of 28-day
strength will exceed 5000 psi when the value of accelerated
strength is 2000? (Round your answer to four decimal places.)
(b)
What is the probability that the...
Assume the measurements of nominal shear strength (in kN) are
normally distributed. To estimate the mean of this distribution, a
sample of 26 measurements was collected with sample mean 678.27 and
the sample standard deviation 82.89. Find a 90% confidence
interval. Please show work. Thanks.
1. A t-test should be used when the standard deviation of the
population is known, whereas a z-test should be used when the
standard deviation of the population is unknown. True or
False?
2. If r = 0.72, what proportion of the variance in
Y is accounted for by it's relationship with
X?
A. .72
b. .52
c. .36
d. .85
3.Jane conducts a Pearson correlation to assess the relationship
between years of marriage and happiness from data collected from...
Consider a pair of 3/8 in welds that are each 10 in long.
Determine the strength if these two welds if:
They are loaded parallel to their length
They are loaded perpendicular to their length
Do not consider simplifying
assumptions
Consider an L5x3x1/2 supporting 45 kip dead load and 30 kip
live load. It is being welded to an ASTM A36 PL5/8x8. Design and
proportion the weld to make this a simple welded connection. The
leg of the weld should...
A distribution of measurements is relatively mound-shaped with
mean 80 and standard deviation 10.
(a) What proportion of the measurements will fall between 70 and
90?
(b) What proportion of the measurements will fall between 60 and
100?
(c) What proportion of the measurements will fall between 60 and
90?
(d) If a measurement is chosen at random from this distribution,
what is the probability that it will be greater than 90?