The answer is C. Stratified random sampling is a method of sampling that involves the division of a population into smaller sub-groups known as strata. In stratified random sampling or stratification, the strata are formed based on members' shared attributes or characteristics such as income or educational attainment. Since the students are divided into classes, this is a stratified random sample.
        
             
        
        
        
Answer:
$281,612
Explanation:
Plane Operating Cost = Fixed cost + (Variable cost per unit1 × q1) + (Variable cost per unit 2 × q2)
Plane Operating Cost = $40,190 + ($2709*88) + ($10 * 303)
Plane Operating Cost = $40,190 + $238,392 + $3,030
Plane Operating Cost = $281,612
So, the plane operating costs in the planning budget for August would be $281,612
 
        
             
        
        
        
<span>Which promotion exemplifies the use of a fixed-ratio schedule of reinforcement? A café prints "you are a winner" on a random one-twelfth of its coffee lids; patrons receiving such a lid can redeem it for a free beverage. A fixed-ratio schedule of reinforcement, which a response is reinforced when there is a set number of responses. Every set number of people purchasing the coffee have a chance to win a free beverage. </span>
        
             
        
        
        
Answer and Explanation:
The subject of the email is too long and contains all the information. The subject should have been: Proposal draft due on Friday. Rest of the information should have been included in the body of the email. 
 
        
             
        
        
        
Answer:
b. $85,000
Explanation:
First, we should prepare the analysis of cost savings if the company buys outside.
Analysis of cost and savings
Purchase (5,000 units × $68) = ($340,000)
Savings
Variable cost = $80,000
Fixed cost = $175,000
Net income effect
($85,000)
The effect is a decrease in net income by $85,000.