Python, PyQt5: как исправить ошибку TypeError?

Вы не правильно даете имена переменным и методам. Ознакомьтесь с руководством по написанию кода на Python https://pythonworld.ru/osnovy/pep-8-rukovodstvo-po-napisaniyu-koda-na-python.html

Виджет QLineEdit - это однострочный текстовый редактор.

Класс QDoubleSpinBox предоставляет виджет счетчика, который принимает значения с плавающей точкой. Больше ... https://doc.qt.io/qt-5/qdoublespinbox.html

И еще некоторые пояснения по тексту программы.

import sys
from PyQt5 import QtCore, QtWidgets, QtGui
from PyQt5.QtGui import QPixmap


class Ui_Form(object):
    def setupUi(self, Form):
        Form.setObjectName("Form")
        Form.resize(500, 450)
        self.lineEdit = QtWidgets.QLineEdit(Form)
        self.lineEdit.setGeometry(QtCore.QRect(40, 197, 113, 20))
        self.lineEdit.setObjectName("lineEdit")
        self.lineEdit_2 = QtWidgets.QLineEdit(Form)
        self.lineEdit_2.setGeometry(QtCore.QRect(200, 197, 113, 20))
        self.lineEdit_2.setObjectName("lineEdit_2")
        self.lineEdit_3 = QtWidgets.QLineEdit(Form)
        self.lineEdit_3.setGeometry(QtCore.QRect(40, 227, 113, 20))
        self.lineEdit_3.setObjectName("lineEdit_3")
        self.lineEdit_4 = QtWidgets.QLineEdit(Form)
        self.lineEdit_4.setGeometry(QtCore.QRect(200, 227, 113, 20))
        self.lineEdit_4.setObjectName("lineEdit_4")
        self.lineEdit_5 = QtWidgets.QLineEdit(Form)
        self.lineEdit_5.setGeometry(QtCore.QRect(350, 197, 113, 20))
        self.lineEdit_5.setObjectName("lineEdit_5")
        self.label = QtWidgets.QLabel(Form)
        self.label.setGeometry(QtCore.QRect(20, 197, 16, 21))
        self.label.setObjectName("label")
        self.label_2 = QtWidgets.QLabel(Form)
        self.label_2.setGeometry(QtCore.QRect(20, 227, 21, 16))
        self.label_2.setObjectName("label_2")
        self.label_3 = QtWidgets.QLabel(Form)
        self.label_3.setGeometry(QtCore.QRect(180, 197, 21, 16))
        self.label_3.setObjectName("label_3")
        self.label_4 = QtWidgets.QLabel(Form)
        self.label_4.setGeometry(QtCore.QRect(180, 227, 16, 16))
        self.label_4.setObjectName("label_4")
        self.label_5 = QtWidgets.QLabel(Form)
        self.label_5.setGeometry(QtCore.QRect(330, 197, 21, 16))
        self.label_5.setObjectName("label_5")
        self.pushButton = QtWidgets.QPushButton(Form)
        self.pushButton.setGeometry(QtCore.QRect(20, 270, 221, 24))
        self.pushButton.setObjectName("pushButton")
        self.pushButton_2 = QtWidgets.QPushButton(Form)
        self.pushButton_2.setGeometry(QtCore.QRect(260, 270, 211, 24))
        self.pushButton_2.setObjectName("pushButton_2")
        self.textEdit = QtWidgets.QTextEdit(Form)
        self.textEdit.setGeometry(QtCore.QRect(20, 300, 451, 141))
        self.textEdit.setObjectName("textEdit")
        self.label_6 = QtWidgets.QLabel(Form)
        self.label_6.setGeometry(QtCore.QRect(0, 30, 500, 150))
        pimax = QPixmap('boy.jpg').scaled(500, 150)
        self.label_6.setPixmap(pimax)
        self.label_6.setObjectName("label_6")

        self.retranslateUi(Form)
        QtCore.QMetaObject.connectSlotsByName(Form)

    def retranslateUi(self, Form):
        _translate = QtCore.QCoreApplication.translate
        Form.setWindowTitle(_translate("Form", "Form"))
        self.lineEdit.setText(_translate("Form", "10"))
        self.lineEdit_2.setText(_translate("Form", "10"))
        self.lineEdit_3.setText(_translate("Form", "10"))
        self.lineEdit_4.setText(_translate("Form", "10"))
        self.lineEdit_5.setText(_translate("Form", "10"))
        self.label.setText(_translate("Form", "Pf"))
        self.label_2.setText(_translate("Form", "Alf0"))
        self.label_3.setText(_translate("Form", "Alf1"))
        self.label_4.setText(_translate("Form", "En"))
        self.label_5.setText(_translate("Form", "Exp"))
        self.pushButton.setText(_translate("Form", "Расчитать"))
        self.pushButton_2.setText(_translate("Form", "Закрыть"))

        
# не делайте множественное наследование, если не знаете зачем вы это делаете
#                                        vvv ???????? vvv    
#class ExampleApp(QtWidgets.QMainWindow, QtWidgets.QLabel , forma.Ui_Form):
class ExampleApp(QtWidgets.QMainWindow, Ui_Form):
    def __init__(self, parent = None):
        super().__init__()
# ?       QtWidgets.QWidget.__init__(self, parent)
        self.setupUi(self)
#        self.pushButton_2.clicked.connect(QtWidgets.QApplication.instance().quit)
        self.pushButton_2.clicked.connect(self.close)
        
#                                                () <--- не нужны !        
#        self.pushButton.clicked.connect(self.Fix())
        self.pushButton.clicked.connect(self.calculate)
        
        font = QtGui.QFont("Consolas", 12) 
        self.textEdit.setFont(font)                               

    def calculate(self):
        pf = float(self.lineEdit.text())
        alf1 = float(self.lineEdit_2.text())
        alf0 = float(self.lineEdit_3.text())
        en = float(self.lineEdit_4.text())
        exp = float(self.lineEdit_5.text())
        
        p1 = 1.1 * pf
        uk = exp * en
        ik1 = (2 * p1) / uk
        ik0 = ik1 * (alf0 / alf1)
        p0 = ik0 * en
        prac = p0 - p1
        h1 = p1 / p0

        self.textEdit.setText('''P1   = {:>7.2f}        
Uk   = {:>7.2f}
Ik1  = {:>7.2f} 
Ik0  = {:>7.2f} 
P0   = {:>7.2f} 
Prac = {:>7.2f} 
h1   = {:>7.2f}'''.format(p1, uk, ik1, ik0, p0, prac, h1))
        

if __name__ == '__main__':
    app = QtWidgets.QApplication(sys.argv)
    window = ExampleApp()
    window.show()
    sys.exit(app.exec_())