A |
absorbance for computing % reduction in bacterial growth from turbidimetric readings. |

b |
slope of the straight line relating response (y) to log-dose (x) [Equations 2b, 4, 5, 6]. |

c |
constant for computing M¢ with Equations 8 and 10. |

c¢ |
constant for computing L with Equations 26 and 29. |

ci |
constant for computing M¢ when doses are spaced as in Table 8. |

c¢i2 |
constant for computing L when doses are spaced as in Table 8. |

C |
term measuring precision of the slope in a confidence interval [Equations 27, 28, 35, 36]. |

2 |
statistical constant for testing significance of a discrepancy [Table 9]. |

M2 |
2 testing the disagreement between different estimates of log-potency [Equations 39, 40]. |

eb |
ei from row b in Tables 6 to 8. |

eb¢i |
multiple of S(x – x)2 [Table 5; Equation 6]. |

ei |
sum of squares of the factorial coefficients in each row of Tables 6 to 8. |

eq |
ei from row q in Tables 6 to 8. |

f |
number of responses at each dosage level of a preparation; number of replicates or sets. |

fS |
number of observations on the Standard. |

fU |
number of observations on the Unknown. |

F1 to F3 |
observed variance ratio with 1 to 3 degrees of freedom in numerator [Table 9]. |

G1, G2, and G3 |
relative gap in test for outlier [Table 1]. |

h |
number of Unknowns in a multiple assay. |

h¢ |
number of preparations in a multiple assay, including the Standard and h Unknowns; i.e., h¢ = h + 1. |

i |
interval in logarithms between successive log-doses, the same for both Standard and Unknown. |

k |
number of estimated log-potencies in an average [Equation 24]; number of treatments or doses [Table 4; Equations 1, 13, 15, 16]; number of ranges or groups in a series [Table 2]; number of rows, columns, and doses in a single Latin square [Equations 1a, 16a]. |

L |
length of the confidence interval in logarithms [Equations 24, 26, 29, 38], or in terms of a proportion of the relative potency of the dilutions compared [Equations 31, 33]. |

Lc |
length of a combined confidence interval [Equations 42, 43]. |

Lc¢ |
length of confidence interval for a semi-weighted mean M [Equation 48]. |

LD50 |
lethal dose killing an expected 50% of the animals under test [Equation 2c]. |

M |
log-potency [Equation 2]. |

M¢ |
log-potency of an Unknown, relative to its assumed potency. |

M |
mean log-potency. |

n |
degrees of freedom in an estimated variance s2 or in the statistic t or 2. |

n¢ |
number of Latin squares with rows in common [Equations 1a, 16a]. |

N |
number; e.g., of observations in a gap test [Table 1], or of responses y in an assay [Equation 16]. |

P |
probability of observing a given result, or of the tabular value of a statistic, usually P = 0.05 or 0.95 for confidence intervals [Tables 1, 2, 9]. |

P* |
potency, P* = antilog M or computed directly. |

R |
ratio of a given dose of the Standard to the corresponding dose of the Unknown, or assumed potency of the Unknown [Equations 2, 30, 33]. |

R* |
ratio of largest of k ranges in a series to their sum [Table 2]. |

s = s2 |
standard deviation of a response unit, also of a single estimated log-potency in a direct assay [Equation 24]. |

s2 |
error variance of a response unit. |

Si |
a log-dose of Standard [Tables 6, 7]. |

S |
“the sum of.” |

t |
Student's t for n degrees of freedom and probability P = 0.05 [Table 9]. |

T |
total of the responses y in an assay [Equation 16]. |

T¢ |
incomplete total for an assay in randomized sets with one missing observation [Equation 1]. |

T1 |
S(y) for the animals injected with the Standard on the first day [Equations 18, 36]. |

T2 |
S(y) for the animals injected with the Standard on the second day [Equations 18, 36]. |

Ta |
Ti for the difference in the responses to the Standard and to the Unknown [Tables 6 to 8]. |

Tab |
Ti for testing the difference in slope between Standard and Unknown [Tables 6 to 8]. |

Taq |
Ti for testing opposed curvature in the curves for Standard and Unknown [Tables 6 to 8]. |

Tb |
Ti for the combined slope of the dosage-response curves for Standard and Unknown [Tables 6 to 8]. |

Tb¢ |
S(x1Tt) or S(x1y) for computing the slope of the log-dose response curve [Equations 10, 23, 28]. |

Ti |
sum of products of Tt multiplied by the corresponding factorial coefficients in each row of Tables 6 to 8. |

Tq |
Ti for testing similar curvature in the curves for Standard and Unknown [Tables 6 to 8]. |

Tr |
row or set total in an assay in randomized sets [Equation 16]. |

Tr¢ |
incomplete total for the randomized set with a missing observation in Equation 1. |

Tt |
total of f responses y for a given dose of a preparation [Tables 6 to 8; Equations 6, 13, 14, 16]. |

Tt¢ |
incomplete total for the treatment with a missing observation in Equation 1. |

Ui |
a log-dose of Unknown [Tables 6 to 8]. |

v |
variance for heterogeneity between assays [Equation 45]. |

V = 1/w |
variance of an individual M [Equations 44 to 47]. |

w |
weight assigned to the M for an individual assay [Equation 38], or to a probit for computing an LD50 [Equations 2a, 2b]. |

w¢ |
semi-weight of each M in a series of assays [Equations 47, 48]. |

x |
a log-dose of drug in a bioassay [Equation 5]; also the difference between two log-threshold doses in the same animal [Equation 12]. |

x* |
coefficients for computing the lowest and highest expected responses yL and yH in a log-dose response curve [Table 4; Equation 3]. |

x1 |
a factorial coefficient that is a multiple of (x – x) for computing the slope of a straight line [Table 5; Equation 6]. |

x |
mean log-dose [Equation 5]. |

xS |
mean log-dose for Standard [Equation 9]. |

xU |
mean log-dose for Unknown [Equation 9]. |

X |
log-potency from a unit response, as interpolated from a standard curve [Equations 7a, 7b, 19]. |

XM |
confidence limits for an estimated log-potency M [Equations 25, 30]. |

XP* |
confidence limits for a directly estimated potency P* (see Digitalis assay) [Equation 33]. |

y |
an observed individual response to a dose of drug in the units used in computing potency and the error variance [Equations 13 to 16]; a unit difference between paired responses in 2-dose assays [Equations 17, 18]. |

y1...yN |
observed responses listed in order of magnitude, for computing G1, G2, or G3 in Table 1. |

y¢ |
replacement for a missing value [Equation 1]. |

y |
mean response in a set or assay [Equation 5]. |

yt |
mean response to a given treatment [Equations 3, 6]. |

Y |
a response predicted from a dosage-response relationship,often with qualifying subscripts [Equations 3 to 5]. |

z |
threshold dose determined directly by titration (see Digitalis assay) [Equation 11]. |

z |
mean threshold dose in a set (see Digitalis assay) [Equations 31, 32, 33]. |