The shear strength of each of ten test spot welds is determined, yielding the following data (psi): 392 376 401 367 389 362 409 415 358 375 you are to design a structure that will be built using spot welds similar to the ten you have measured. in order to ensure that the structure is reliable, you'll want to infer a distribution from this data. (a) assuming that the shear strength is normally distributed, estimate the av- erage and standard deviation of its distribution using the moment-matching method. (b) again assuming a normal distribution, estimate the weld strength value above which 95% of all weld strengths will be. assume that the actual standard deviation is known and equal to the one estimated from the data. (c) repeat the previous two steps, but now assume a lognormal distribution. (use the moment matching method to estimate the parameters of your lognormal distribution.) how much did your answer to part b change?

a. -0.3 > -0.33

d. $180

step-by-step explanation:

if the dimensions of the room is 9ft by 12 ft, we have the area of the floor as,

so the area of the floor is 108 square feet, converting that into square yards we get,

the cost of carpet is $15 per square yard, therefore the cost of carpet for 12 square yards is,

hence, the cost of carpet is $180.

assuming the dimensions of the room be,

15 ft by 12 ft

so, the area of the floor of that room is,

we can convert 180 square feet into square yards, we know that,

1 sq ft = 0.111 sq yard

so, 180 square feet is,

so the area of floor is 20 square yards.

now, the cost of carpet is 15 dollars per square yard, therefore the cost of carpet for 20 square yards is,

so, it will cost $300.

step-by-step explanation:

the ratio of red paint to blue paint is always 9/7. that means that, whatever x's value, (4x+12)/(4x-4) has that same ratio. so, set up an equation and cross-multiply to solve for x:

9/7 = (4x+12)/(4x-4)

9(4x-4) = 7(4x+12)

36x - 36 = 28x + 84

8x - 36 = 84

8x = 120

x = 15