I

icon sets, 164–165, 172–173.

See also conditional formatting

icons, sorting by, 189

IF formulas

AND formulas and, 78

for cost as function of order quantity, 74–75

defined, 74

with MOD() function, 85

nesting, 85

OR formulas and, 79

percentage return calculation with, 75–76

with ROW() function, 85

IFERROR function, 83

importing

stock information, 267–268

from text files, 259–263

from Web pages, 265–267

independent variables

Central Limit Theorem and, 468–469

defined, 365, 448

interaction, 406

interaction, testing for, 406

nonlinear effect on dependent variables, 405

nonlinearity, testing for, 406

INDEX function

columns/rows, referencing with, 20

implementing, 20

syntax, 19

INDIRECT function

cell references in, changing, 158–159

defined, 157

example of, 157

as range name, 161

INTERCEPT function, 371

internal rate of return (IRR).

See also IRR function;

XNPV function

calculating, 52

for irregularly spaced dates, 54

modified, 54–55

multiple, 52–53

multiple, checking for, 52

unique, guarantee of, 53–54

Internet content. See Web pages

invalid data alerts. See data validation

inventory, reordering. See Economic Order Quantity formula;

reorder point

investments, simulating future returns on. See bootstrapping

IPMT function, 61–62

IRR. See internal rate of return (IRR)

IRR function.

See also internal rate of return (IRR)

guess argument, default, 52

syntax, 52

ISNUMBER function, 272

iterative calculation, enabling, 70