Questions 11–20 of 65. Imported answers require independent review unless marked reviewed.

Topic practice 65 questionsPage 2 of 7

Question 11

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Suppose

and

are random variables. The conditional expectation of

given

is denoted by

. Then

equals
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Question 12

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The number of additions and multiplications involved in performing Gaussian elimination on any

upper triangular matrix is of the order
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Question 13

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The sum of the elements in each row of

is 1. If

, which one of the following statements is correct (for

)?
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Question 14

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Let

,

. Let

denote the

th derivative of

evaluated at

. What is the value of

? (Note:

denotes factorial)
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Question 15

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Let

and

be any two propositions. Consider the following propositional statements.

where

denotes conjunction (AND operation),

denotes disjunction (OR operation), and

denotes negation (NOT operation). Which one of the following options is correct?
(Note:

denotes logical equivalence)
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Question 16

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If a relational decomposition is not dependency-preserving, which one of the following relational operators will be executed more frequently in order to maintain the dependencies?
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Question 17

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Consider the following three relations:
Car (model, year, serial, color)
Make (maker, model)
Own (owner, serial)
A tuple in Car represents a specific car of a given model, made in a given year, with a serial number and a color. A tuple in Make specifies that a maker company makes cars of a certain model. A tuple in Own specifies that an owner owns the car with a given serial number. Keys are underlined; (owner, serial) together form key for Own. (

denotes natural join)

Which one of the following options describes what the above expression computes?
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Question 18

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Consider a hash table of size 10 with indices

, with the hash function

where linear probing is used to handle collisions. The hash table is initially empty and the following sequence of keys is inserted into the hash table: 1, 4, 5, 6, 14, 15. The indices where the keys 14 and 15 are stored are, respectively
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Question 19

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Let

be a continuous random variable whose cumulative distribution function (CDF)

, for some

, is given as follows:

If the median of

is 3, then what is the value of

?
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Question 20

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Let

, where

is a standard normal random variable, and

are two unknown constants. It is given that

where

denotes the expectation of random variable

. The values of

are:
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